American know how.

[Pedro_The_Swift]

I watched a vid posted by one of our American friends,, and while I had no clue as to the loud tapping,, I did notice this,,
and I dont mean the red inlet manifold:p

[lewy]

what part of the US,could it be a water heater

[northiam]

This?
JEGS In-Line Thermostat Housing | JEGS Performance Products (http://www.jegs.com/p/JEGS-Performance-Products/JEGS-In-Line-Thermostat-Housing/2677715/10002/-1)

[PhilipA]

I still have problems working out how they work.

Where does the temperature signal come from to open them?

Is it just the water in the pipe nearer to the head , so that it could be much cooler than the water in the head itself.

IMHO you would need a bleed of hot water into the hose near the thermostat from the water pump.
It was these doubts that led me to pay hundreds to machine the Thor manifold I fitted to a 3.9 to accept a normal thermostat in the accustomed position which worked well..
AFAIK that is one reason you have the complicated bypasses in the factory thermostat.
Regards Philip A

[northiam]

how the cooling system works, basics | Grumpys Performance Garage (http://garage.grumpysperformance.com/index.php'threads/how-the-cooling-system-works-basics.853/)

Drill a little hole(s) to maintain some flow for sensing:)

[Chubbs878]

I wrote in a thread the other day that we have been converting the LR cooling system to the inline thermostat setup. The whole point is to eliminate the bypass loop and external thermostat housing. All kinds of benefits.

[Pedro_The_Swift]

The whole point is to eliminate the bypass loop and external thermostat housing. All kinds of benefits.

we're all listening,,:D

no pressure;):angel:

[Mark Adams]

I wrote in a thread the other day that we have been converting the LR cooling system to the inline thermostat setup. The whole point is to eliminate the bypass loop and external thermostat housing. All kinds of benefits.
Sorry but I totally disagree. I've been doing a lot of research and testing on these to find the best solution, and I'm a total convert to the Pressure Relief Thermostat (PRT) system.

What I have learned though extensive reading and testing, is that I had totally misunderstood (for years!) how the system works and the benefits it gives.

I have run engines covered in thermocouples to find out what goes on inside it, and it's quite a different story to what you see at the coolant outlet on the manifold.

The PRT bypass port is closed by the thermostat as it opens. What it does do is to stabilise the block temperature, as the water inlet to the pump is blended. Without it, the block temperature goes up and down by several degrees as the thermostat opens and closes. It is far more stable with a PRT, which reduces thermal stress between the block and liners.

In the case of the old thermostat in the top hose (which has served very well for over fifty years), there is also only one place for the water to go when the thermostat is closed. Of course that is the heater, which has to take the full flow. With the PRT there is the bypass circuit as well, which is fully available when the thermostat is closed.

When the thermostat opens, water is blended (hot with cold from the radiator) before being fed back to the engine. Because the bypass is open the flow is much faster through the engine block and head, so the temperature of the water coming down the bypass much more accurately reflects the block temperature.

Originally this system was developed to stabilise the temperature in smaller engines, with Cast Iron Wet Liners seated in Aluminium alloy cylinder blocks. The reason a stable temperature was required was that the rapid increases and drops in the temperature around the cylinder liners would cause them to un-seat from the block, and lead to leaks around the base of the liner seat and early head gasket failure.

I have measured this in some cases with a four cylinder engine, and found that in typical conditions the thermostat outlet temperature drops by 2-3 degrees after the thermostat opens, but it has taken some time for the cold water from the radiator to go through the water pump and all around the block to reach the thermostat. Where the water enters the block, the temperature will vary by 8-12 degrees (Centigrade of course). With a PRT, the temperature is stable throughout within 1-2 Degrees.

Although I cannot find any proof of this, I believe the principle was developed by Honda (I may be very wrong with that), as they were amongst the first to use this type of system. Since then, nearly every modern production car uses this system; partly for emissions, partly for longevity.

PRTs crossed from Honda to Rover (with the introduction of the K-Series engine), and then on to Land Rover. All Land Rover V8s since the arrival of the Disco 2 have used this system, as do Jaguar, BMW, etc.

We all know that car manufacturers are a tight bunch, and won't put anything there unless it's absolutely required. PRTs cost more, so there must be a reason.

As far as I can see, the only challenge with the PRT is the massive lack of choice of opening temperatures. All European Disco 2 and Range Rover P38 V8 motors came with a 92 'stat, which means they run at 95-96 degrees normally.

Whilst there was an 82 Degree hot climate 'stat available for the D2, it has long since been obsolete. This would have given an operating temperature of 85 Degrees, which is pretty much ideal for a road-going V8. I have recently bought loads of different 'stats (many advertised as 82 Degree) to test, but most of them have turned out to be 87 Degree. Nonetheless, that gives an operating temperature of 90 Degrees, which is still better than 95 Degrees. Tomorrow I am testing yet another 82 Degree version, and I have high hopes for this one. Of course I'll let you know what I find.

Out of interest, 95 Degrees is the point at which the Rover V8 starts to lose power. The difference between 95-102 Degrees is around 15 BHP lost. Heat is also a factor in facilitating the dreaded slipped liner.

I'm in the process of converting all my top-thermostat V8s to PRTs, and the results look very good so far.

However, I always have an open mind... ;)

[Pedro_The_Swift]

Wow, Mark,, an AULRO exclusive??:D

as someone whos slipped a liner or two the blended temps sound good,,

[Chubbs878]

we're all listening,,:D

no pressure;):angel:

We route the bottom radiator hose directly to the water pump. The top radaitor hose goes straight to the manifold outlet with the inline thermostat housing, a high-flow 180 degree Chevrolet style Stant Superstat and a Glowshift water temperature sender with a petcock release valve for purging the air out. What we are seeing is operating temps in the 180s with much less fluctuation in temperature. Where we were getting 10-20 degree temp spikes with the LR stat and stock setup, we are now seeing up to 10 degrees at the very most. I'm between 183-83.8 and 189-87.2 and sometimes it will break 190-87.7 with the AC running.

The stock setup and a 180-82.2 LR stat would give me operating temps around 194-90 and spikes up to 204-95.5 regularly. And that's with the heater on full blast 24-7 while driving, otherwise the spikes would be higher but I never cared to find out just how high it would go. I didn't want to drive around with my heater on full-blast here in Dallas for the next 4 months as ambient air temps will exceed 100F-37C for sometimes 30-40 days straight without any relief. Besides that, we attribute the block, cylinder liner and head gasket failures to the higher operating temps and the dramatic temp swings of the factory cooling setup. There is a VERY large number of people on board with this mod and there had not been a single negative incident or failure that I have yet to hear of. I don't know what the hell this other guy is talking about. The proof is in the coolant temps. I didn't even bother to read what he says or whatever research he has done. There are HUNDREDS of threads and write-ups on the topic and this is 1 (count---"1", one) person versus the hundreds who have also researched tirelessly the facts and numbers behind both systems. One more time, i personally went from 194-90 operating temp with swings to 204-95.5 with blower fan on high and heat switched to high so the pressure remains equalized, to 183-83.8 operating temps and swings to 189-87.2 with the cold AC at any setting to my comfort level. Of course I previously updated all hoses and equipment, viscous clutch/fan, and green ethylene antifreeze/distilled water. Obviously it's also in everyone's best interest to get as far away from the DexCool as you can. DexCool, high coolant temps and even higher temp swings are to blame for the failures the Disco2 is famous for. And obviously lack of maintenance.

[Bohica]

I didn't even bother to read what he says or whatever research he has done.

I read it, and I have a diesel, still interesting and convincing from an engineering - science perspective.


Cheers

Bo

BSc Adelaide, Grad Dip Sec Ed. VU

[Battler]

This mod is on my to do list. I want to keep the temp at or below 90.

Isn't the original design something to do with getting the heater matrix hot as fast as possible and keeping it hot?

[Mark Adams]

I don't know what the hell this other guy is talking about. The proof is in the coolant temps. I didn't even bother to read what he says or whatever research he has done.
That's a pity, as I always keep an open mind. I read what you have to say, as I thought we were all here to learn... :)

[Mark Adams]

how the cooling system works, basics | Grumpys Performance Garage (http://garage.grumpysperformance.com/index.php'threads/how-the-cooling-system-works-basics.853/)

Drill a little hole(s) to maintain some flow for sensing:)
May be a little childish of me, but I love those clear water pipes on that beautiful chromed V8! I'd love to know how long they'd last...

[Battler]

Here we go; from RAVE:

General
The cooling system used on the V8 engine is a pressure relief by-pass type system which allows coolant to circulate around the cylinder block and the heater circuit when the thermostat is closed. With coolant not passing through the
radiator, this promotes faster heater warm-up which in turn improves passenger comfort.

By-pass flow valve
The by-pass flow valve is held closed by a light spring. It operates to further aid heater warm-up. When the main valve is closed and the engine speed is at idle, the coolant pump does not produce sufficient flow and pressure to open the
valve. In this condition the valve prevents coolant circulating through the by-pass circuit and forces the coolant through the heater matrix only. This provides a higher flow of coolant through the heater matrix to improve passenger comfort
in cold conditions.

[PhilipA]

To our American cousins.
Mark Adams has considerable street cred with the Land Rover enthusiasts around the World and if he has done research on thermostat operation, I for one would listen to him.

You can be excused I guess from not knowing of his experience down there in Texas.

This is Mark Adams' company

Tornado Systems | Engine Management Technology Specialists (http://www.tornadosystems.com/)

Regards Philip A
PS I really don't think that quoting from Rave is qualitatively equivalent to actual research done by a RV8 specialist.

[Chubbs878]

To our American cousins.
Mark Adams has considerable street cred with the Land Rover enthusiasts around the World and if he has done research on thermostat operation, I for one would listen to him.

You can be excused I guess from not knowing of his experience down there in Texas.

This is Mark Adams' company

Tornado Systems | Engine Management Technology Specialists (http://www.tornadosystems.com/)

Regards Philip A
PS I really don't think that quoting from Rave is qualitatively equivalent to actual research done by a RV8 specialist.

I'm sorry about my comment. We are on opposing sides, so I really just don't have any interest in the bypass and external thermostat blending at the radiator outlet. If that worked on these trucks, they wouldn't be a dime-a-dozen parts trucks and recyclables with blown engines; you wouldn't be able to buy them for $3500 US on any given day. The Disco has no resale value because of its reputation for vomiting head gasket and cylinder liners. All of these problems are related to the OAT coolant and operating temps. Think about it. Get away from the bypass loop and save what's left of your Rover V8. Nothing but success stories and happy enthusiasts as result of the thermostat mod. We should be talking about that and not entertaining ideas of a bypass system on the old Disco. LR engineering dropped the ball on this one. 180 degree Thermostat on the outlet manifold would have probably prevented catastrophic failures on all of these aluminum blocks. The liners can't slip of the temp stays under 200F. Obviously a fully and reliably functioning temperature gauge would help the overheating incidents as well. Don't know how they work on overseas models, but over here we deal with a 3-position temp switch that reads stone-cold, 150-230 center of gauge, and HOT but the warning is already too little, too late. It seems to me that LR WANTED to blow every last engine.

[Battler]

To our American cousins.
Mark Adams has considerable street cred with the Land Rover enthusiasts around the World and if he has done research on thermostat operation, I for one would listen to him.

You can be excused I guess from not knowing of his experience down there in Texas.

This is Mark Adams' company

Tornado Systems | Engine Management Technology Specialists (http://www.tornadosystems.com/)

Regards Philip A
PS I really don't think that quoting from Rave is qualitatively equivalent to actual research done by a RV8 specialist.

Wow! Shots fired!

One at me for supporting my comment on the intentional design of the bypass system by providing information from the manufacturer and one at the Texans.

I have the upmost respect for Mark Adams. I was extremely happy with the conversations I had with him and the work he did for me on my ECM for my modified 4.6L. However, in your link there is a clue as to what Mark is a specialist in, and most likely is the best in the world. And, by his own admission by saying he has an open mind, he is not a specialist in engine cooling systems.

From what I have read on other forums (in particular landroverforums.com), many D2 owners in USA have done this modification which reduced and stabilised their operating temperature range without any issues in a variety of climates. This has to be a good thing?

I must state I too am not a specialist in cooling systems (or anything else related to Land Rover) and I also have an open mind.

[Chubbs878]

To our American cousins.
Mark Adams has considerable street cred with the Land Rover enthusiasts around the World and if he has done research on thermostat operation, I for one would listen to him.

You can be excused I guess from not knowing of his experience down there in Texas.

This is Mark Adams' company

Tornado Systems | Engine Management Technology Specialists (http://www.tornadosystems.com/)

Regards Philip A
PS I really don't think that quoting from Rave is qualitatively equivalent to actual research done by a RV8 specialist.

What are you talking about? I never quoted RAVE. Furthermore, Land Rover engineers were also RV8 "specialists." That still doesn't make them right. Honestly, I would put more trust into someone who specializes in anything but Rovers, and utilizes that knowledge to improve the lesser-quality, poorly engineered mechanicals that is the Rover.

[Chubbs878]

To our American cousins.
Mark Adams has considerable street cred with the Land Rover enthusiasts around the World and if he has done research on thermostat operation, I for one would listen to him.

You can be excused I guess from not knowing of his experience down there in Texas.

This is Mark Adams' company

Tornado Systems | Engine Management Technology Specialists (http://www.tornadosystems.com/)

Regards Philip A
PS I really don't think that quoting from Rave is qualitatively equivalent to actual research done by a RV8 specialist.

What are you talking about? I never quoted RAVE. Furthermore, Land Rover engineers were also Rover "specialists." That still doesn't make them right. Honestly, I would put more trust into someone who specializes in anything but Rovers, and utilizes that knowledge to improve the lesser-quality, poorly engineered mechanicals that is the Rover.

[Battler]

What are you talking about? I never quoted RAVE. Furthermore, Land Rover engineers were also RV8 "specialists." That still doesn't make them right. Honestly, I would put more trust into someone who specializes in anything but Rovers, and utilizes that knowledge to improve the lesser-quality, poorly engineered mechanicals that is the Rover.

I'm sure that was fired at me Chubbs878 and not you. Please read my response above.

[Chubbs878]

Wow! Shots fired!

One at me for supporting my comment on the intentional design of the bypass system by providing information from the manufacturer and one at the Texans.

I have the upmost respect for Mark Adams. I was extremely happy with the conversations I had with him and the work he did for me on my ECM for my modified 4.6L. However, in your link there is a clue as to what Mark is a specialist in, and most likely is the best in the world. And, by his own admission by saying he has an open mind, he is not a specialist in engine cooling systems.

From what I have read on other forums (in particular landroverforums.com), many D2 owners in USA have done this modification which reduced and stabilised their operating temperature range without any issues in a variety of climates. This has to be a good thing?

I must state I too am not a specialist in cooling systems (or anything else related to Land Rover) and I also have an open mind.

Deleted this comment after some thought.

[Chubbs878]

Sorry but I totally disagree. I've been doing a lot of research and testing on these to find the best solution, and I'm a total convert to the Pressure Relief Thermostat (PRT) system.

What I have learned though extensive reading and testing, is that I had totally misunderstood (for years!) how the system works and the benefits it gives.

I have run engines covered in thermocouples to find out what goes on inside it, and it's quite a different story to what you see at the coolant outlet on the manifold.

The PRT bypass port is closed by the thermostat as it opens. What it does do is to stabilise the block temperature, as the water inlet to the pump is blended. Without it, the block temperature goes up and down by several degrees as the thermostat opens and closes. It is far more stable with a PRT, which reduces thermal stress between the block and liners.

In the case of the old thermostat in the top hose (which has served very well for over fifty years), there is also only one place for the water to go when the thermostat is closed. Of course that is the heater, which has to take the full flow. With the PRT there is the bypass circuit as well, which is fully available when the thermostat is closed.

When the thermostat opens, water is blended (hot with cold from the radiator) before being fed back to the engine. Because the bypass is open the flow is much faster through the engine block and head, so the temperature of the water coming down the bypass much more accurately reflects the block temperature.

Originally this system was developed to stabilise the temperature in smaller engines, with Cast Iron Wet Liners seated in Aluminium alloy cylinder blocks. The reason a stable temperature was required was that the rapid increases and drops in the temperature around the cylinder liners would cause them to un-seat from the block, and lead to leaks around the base of the liner seat and early head gasket failure.

I have measured this in some cases with a four cylinder engine, and found that in typical conditions the thermostat outlet temperature drops by 2-3 degrees after the thermostat opens, but it has taken some time for the cold water from the radiator to go through the water pump and all around the block to reach the thermostat. Where the water enters the block, the temperature will vary by 8-12 degrees (Centigrade of course). With a PRT, the temperature is stable throughout within 1-2 Degrees.

Although I cannot find any proof of this, I believe the principle was developed by Honda (I may be very wrong with that), as they were amongst the first to use this type of system. Since then, nearly every modern production car uses this system; partly for emissions, partly for longevity.

PRTs crossed from Honda to Rover (with the introduction of the K-Series engine), and then on to Land Rover. All Land Rover V8s since the arrival of the Disco 2 have used this system, as do Jaguar, BMW, etc.

We all know that car manufacturers are a tight bunch, and won't put anything there unless it's absolutely required. PRTs cost more, so there must be a reason.

As far as I can see, the only challenge with the PRT is the massive lack of choice of opening temperatures. All European Disco 2 and Range Rover P38 V8 motors came with a 92 'stat, which means they run at 95-96 degrees normally.

Whilst there was an 82 Degree hot climate 'stat available for the D2, it has long since been obsolete. This would have given an operating temperature of 85 Degrees, which is pretty much ideal for a road-going V8. I have recently bought loads of different 'stats (many advertised as 82 Degree) to test, but most of them have turned out to be 87 Degree. Nonetheless, that gives an operating temperature of 90 Degrees, which is still better than 95 Degrees. Tomorrow I am testing yet another 82 Degree version, and I have high hopes for this one. Of course I'll let you know what I find.

Out of interest, 95 Degrees is the point at which the Rover V8 starts to lose power. The difference between 95-102 Degrees is around 15 BHP lost. Heat is also a factor in facilitating the dreaded slipped liner.

I'm in the process of converting all my top-thermostat V8s to PRTs, and the results look very good so far.

However, I always have an open mind... ;)

In the spirit of open-mindedness, I did entertain the notion of keeping my system stock and replacing the LR 180 I had with this BMW housing and one of their 180 deg stats. Mark, you should try one of these to lower the temps further. eBay has Tstats in a variety of temp ratings starting at 160 which was the factory model.

[Pedro_The_Swift]

Funnily enough the lowering of operating temps for V8 D2's has been a high priority for D2's pretty much all round the world,,, :angel:;)

just that in OZ ( and we obviously followed England, who'd a thunk?? ) we used factory parts,, who knows why we didnt look at Nth America?? all our parts manuals tell us you're there-- ;)


your way of lowering temps is new to us.. :D

[peter51]

Sorry, but I don't think that the current system is some special design - However only the project engineers could truly confirm any of our theories.

Car manufacturers no longer listen to engineers - nor do most executives of major companies in Australia or elsewhere. They are only sales driven and bonus driven. Their only motivation is the great human motivator " what's in it for me", and so sales and marketing trump function and longevity.In this case, the fundamental emphasis was to provide faster heater matrix warm up, which they probaly garnered from a customer survey.

The engineers then had to come up with a compromise solution. This is the cooling system we have in the Discovery and P38.

I can just imagine the engineers complaining, but being sarcastically howled down by the executives. The engineers parting words would have been " this decision will come back to haunt you in poor reliability".

The poor engineer would have been told to go elsewhere if he didn't like the decision from the "design team".

I'm with the Texas camp on this one. It's simple and it works.

Could I ask chubs878 to post some pictures please and some part numbers for hoses, thermostat housing etc so I can follow suit. I'll be changing over ASAP.

[Chubbs878]

Sorry, but I don't think that the current system is some special design - However only the project engineers could truly confirm any of our theories.

Car manufacturers no longer listen to engineers - nor do most executives of major companies in Australia or elsewhere. They are only sales driven and bonus driven. Their only motivation is the great human motivator " what's in it for me", and so sales and marketing trump function and longevity.In this case, the fundamental emphasis was to provide faster heater matrix warm up, which they probaly garnered from a customer survey.

The engineers then had to come up with a compromise solution. This is the cooling system we have in the Discovery and P38.

I can just imagine the engineers complaining, but being sarcastically howled down by the executives. The engineers parting words would have been " this decision will come back to haunt you in poor reliability".

The poor engineer would have been told to go elsewhere if he didn't like the decision from the "design team".

I'm with the Texas camp on this one. It's simple and it works.

Could I ask chubs878 to post some pictures please and some part numbers for hoses, thermostat housing etc so I can follow suit. I'll be changing over ASAP.

I intended to do so yesterday but was discouraged as the compatibility of the mobile website and the iPhone doesn't allow me to post more than 1 photo with a post. I will have something for you guys by tomorrow. Furthermore, I have already improved upon the modification as seen in the US instructions but have yet to do it myself, so you guys will be the first to utilize the new and improved.

[Chubbs878]

Funnily enough the lowering of operating temps for V8 D2's has been a high priority for D2's pretty much all round the world,,, :angel:;)

just that in OZ ( and we obviously followed England, who'd a thunk?? ) we used factory parts,, who knows why we didnt look at Nth America?? all our parts manuals tell us you're there-- ;)


your way of lowering temps is new to us.. :D

There have been a couple of threads that I found on the inline setup dating back to 2012, but when LR came out with the 180-deg "soft spring" Tstat, everyone ditched the inline-tstat mod in favor of this which required no modification. When engines were still failing enthusiasts discovered with the help of their aftermarket temperature gauges that the thermostats weren't running a whole lot cooler than the factory stat, and the 20-degree spikes were still present. Even their 180 stat runs at 190 and spikes almost to 210 with the AC running so back to the inline-mod they went. And furiously for the past 6-12 months as we now have substantial data dating back several YEARS to our forefather's efforts and conquests of which to confirm the validity and benefits of running the inline stat. I will tell you guys what I told another member just this morning who said he was comfortable with his Disco (also in TX) operating at 210 and spiking to 218F with the AC on, in traffic, because he has over 200K miles and no issues to date. And that is my truck which I bought a year ago, started ticking/tapping a couple weeks later so I asked the PO what was going on. His statement to me was that "all Discos have a tick and that's what they are famous for." I knew the tick was something which was being caused by something. I started searching forums and the first thing I found was the factory temp gauge doesn't work. That made sense as I had the water pump go out on me the 2nd week of ownership and I saw steam before the needle on the gauge cluster ever moved! Next I put my OBD with live data readout to it and immediately saw 218F at idle. That's when I replaced everything including the thermostat (with LR180) and flushed the DexCool in favor of generic green ethylene antifreeze. I was then experiencing operating temps of 194-200F. The "tick/tap" noise was gone and has yet to return. I became obsessed with lower operating temps on this truck right then and there, especially having read numerous stories of slipping cylinder liners and the block cracking behind the liners, inbetween the bores and around the head bolt threads. We also found that other members who had the same tapping sound resolved that issue by lowering the operating temps and so it has become an epidemic. I still don't know what was making the noise at higher temps. Could it have been the cylinder/cylinderS liners moving? Possibly. That's seems to be the general consensus. But the point is that if the temps are low enough, the cylinder liners never get the change to move or loosen inside the overheated and expanded cylinder bore, thereby preventing serious issues and catastrophic failure.

[ozscott]

Mate, thanks for taking the time to post up the info.

2 questions with the lower temps

1. Has anyone noticed any loss of engine efficiency (fuel economy/slightly rough running etc) and 2. Why didnt you like Dexcool given that the gaskets in the D2 are not affected by it like early GM V6 motors were and where Dexcool has a very high boiling point (ie just in case a component fails or there is sudden coolant loss etc it gives a margin of safety)?

Cheers

[ozscott]

I'm sorry about my comment. We are on opposing sides, so I really just don't have any interest in the bypass and external thermostat blending at the radiator outlet. If that worked on these trucks, they wouldn't be a dime-a-dozen parts trucks and recyclables with blown engines; you wouldn't be able to buy them for $3500 US on any given day. The Disco has no resale value because of its reputation for vomiting head gasket and cylinder liners. All of these problems are related to the OAT coolant and operating temps. Think about it. Get away from the bypass loop and save what's left of your Rover V8. Nothing but success stories and happy enthusiasts as result of the thermostat mod. We should be talking about that and not entertaining ideas of a bypass system on the old Disco. LR engineering dropped the ball on this one. 180 degree Thermostat on the outlet manifold would have probably prevented catastrophic failures on all of these aluminum blocks. The liners can't slip of the temp stays under 200F. Obviously a fully and reliably functioning temperature gauge would help the overheating incidents as well. Don't know how they work on overseas models, but over here we deal with a 3-position temp switch that reads stone-cold, 150-230 center of gauge, and HOT but the warning is already too little, too late. It seems to me that LR WANTED to blow every last engine.
Quite a few of us just use a Scanguage or Ultraguage to keep an eye on temps. Ultra has benefit of being able to set an audio and visual alarm at whatever temp.

Cheers

[Chubbs878]

Quite a few of us just use a Scanguage or Ultraguage to keep an eye on temps. Ultra has benefit of being able to set an audio and visual alarm at whatever temp.

Cheers

You have to think, not every Discovery owner is an enthusiast. You are living in a fantasy world having the benefit of this knowledge. How many millions of soccer moms just got in the thing to go for years. There are even board members out there who are STILL referencing the factory temp gauge. I had to tell a guy the other day to stop doing that. I wasn't referring to myself in that post so you are preaching to the choir. I was just saying that there have been millions of people using that gauge who don't know any better, even today after all of the info that is out there on the web and word of mouth. That gauge has led to more problems.... Everyone out there isn't aware of the quirk. They just assume it operates like the temp gauge in every other car that they've ever owned. "Hmmmm steam??! Why is my gauge still in the middle at normal??" Must be something else so I suppose it will make it to the house." PSYCHE! Many a Disco has ended up in a scrap-heap from this exact scenario. Been there, done that. Luckily I had the sense to pull over and cut it off then do some research. Most people don't care that much. They aren't going to join a forum and spend hours reading others rants and opinions on the Internet. They drop it off at a repair garage, pay the bill, and drive it again until it really does **** the bed. I mean just the fact that you have to find this information and even invest in an aftermarket gauge to monitor engine temps should be substantial enough that LR called a bulletin and replaced the sending unit, reprogram the ECU to correlate temps on a sliding scale. And then you want to waste your time posting a response to me about your Scangauge?! Cmon dude. Unbelievable. You obviously don't even get what this whole thread is based on so don't even worry about it.

[ozscott]

Yep the stock temp guage is idiotic. The D1 was better but not great.. It would seem the average driver gets worried to see the temp guage fluctuate. I have cooked my 4.0 at 120 on the Scanguage before the dash needle moved.

Is it easier to bleed air from the heater matrix with the inline stat set up?

Cheers

[Pedro_The_Swift]

As far as I know,, all V8's left the factory with a 96 deg thermostat,, so temps over 100 are common here.

[Chubbs878]

Yep the stock temp guage is idiotic. The D1 was better but not great.. It would seem the average driver gets worried to see the temp guage fluctuate. I have cooked my 4.0 at 120 on the Scanguage before the dash needle moved.

Is it easier to bleed air from the heater matrix with the inline stat set up?

Cheers
I never had any problems with the factory setup and the converted style was no problem at all. I let it idle for almost an hour and it never broke 183. Heat and blower on high, loosened the purging valve screw when it hit 180. Pulled the front tires up onto curb and let it run another 30 mins like that and tweaked open the valve again for good measure. You do have to drill a 1/8 inch hole in the new stat and orient the stat into the housing with the hole on top at 12 o'clock. This is supposed to really allow any air bubbles to escape past and then straight out of the valve. Some guys have positioned the valve first before the thermostat housing on the top hose assembly using the excuse that there is not enough room to place the housing first and this is completely untrue. The housing needs to come first directly after the water outlet pipe above the alternator pulley. It sits fine there. The purge device comes next and then hosing to radiator. Everyone has been piecing together a few sections of hose to make the loop back to driver side of the radiator but I found that a length of the flexible stainless steel hose will accomplish the task in extraordinary fashion and look professional to boot.

You need this hose.. It's the 48-inch kit with reducers/hose adapters, finishers, and stainless clamps from Classic Industries number S7311

[Chubbs878]

1-1/4 inch inline thermostat housing by Meziere, part number WN0071

[Chubbs878]

Glowshift brand 1-1/4 inch water-temp sender

[Chubbs878]

Stant Superstat 180 degree high-flow, Chevrolet/GM style thermostat with 1/8-inch hole tapped and oriented to the 12 o'clock position in housing

[Chubbs878]

TruFlate 21-555 petcock or 1/8-inch valve of your choice to use as a bleeder with the 1-1/4 (32mm) glowshift adapter. You can purchase a Glowshift temp gauge to install here after the air is purged out.

[Chubbs878]

All of that was for the upper conversion. For the lower, you either remove the lower 1-1/2 inch radiator hose from the "Wye" and install Gates hose number 23405, for BMW.

OR, you can leave the stock bypass hose (with the big loop to upper stock Tstat) on the water pump and connect it directly to the stock 1-1/2 lower radiator hose with a barbed or threaded coupling. Here is a pic of both. I'd have had a hard time removing the clamp holding bypass hose to the plastic Wye, so I left it be and coupled it to the radiator hose with a 1-1/2 poly spa coupling from the big-box store up the street. I felt like there was too much tension having stretched the bypass hose down that 4 inches to the lower rad hose but there is no fault in performance or function but when I install the upper flexible/stainless radiator hose, I'm going to remove the short barbed coupling and switch to a longer 3-inch "nipple" type which is used in plumbing. The spa variety of couplers are barbed instead of threaded like pipe so they work perfectly for coupling radiator hoses as they come in different diameters. The top hoses are 1-1/4, lowers are 1-1/2.

[Chubbs878]

Pic of 2 lower hoses being couples together with 1-1/2 spa variety from Home Depot

[Chubbs878]

Another one

[Chubbs878]

Upper assembly pieced together using leftover stock hoses. I used a 1-1/4 spa coupler halfway down. Nobody has done it yet but the flexible stainless hose should be used here. You can google images of different setups enthusiasts have oriented over the years. There are several ways to do this but don't be fooled by a lot of the images that you will find. The Tstat housing needs to be immediately first, then the adapter following. Therefore, the pics that show the new inline housing fitted into the factory radaitor cowling where some finesse grinding and cutting has been done to situate it will not work as well.


This is a picture of mine showing the correct orientation of the assembly. I am in the depths of another project right now so I haven't yet installed the flexi upper hose yet, but this is how it currently stands

[Battler]

Parts ordered from JEGS in the USA. $174 including delivery. Should be delivered in 2 - 5 days.

Anybody looked at putting the inline housing in the metal pipe that comes out of the inlet manifold and therefore getting it even closer to where it should be?

I don't know how big the inline housing is but looking at photos it looks like it might fit. Only need to take off the belt and the AC compressor to get to it. Then put the bleeder where the existing one (or keep the existing one) is with a 90 bend.

Thoughts?

[Pedro_The_Swift]

I'd keep as many joints out in the open where you can watch for leaks, :angel:
I'm not sure that 30cm is worth the trouble.

[Battler]

You may be right Pedro, but it would look a lot neater!

[ozscott]

Parts ordered from JEGS in the USA. $174 including delivery. Should be delivered in 2 - 5 days.

Anybody looked at putting the inline housing in the metal pipe that comes out of the inlet manifold and therefore getting it even closer to where it should be?

I don't know how big the inline housing is but looking at photos it looks like it might fit. Only need to take off the belt and the AC compressor to get to it. Then put the bleeder where the existing one (or keep the existing one) is with a 90 bend.

Thoughts?

I can feel a write up coming on...:cool:

Did you use a thermostat that is easy to source locally in Aus?

Cheers

[Battler]

Yeah, here is the description from the JEGS website:

Thermostat:

GM, Ford, AMC
180? Thermostat
Fits Applications:
1966-1988 AMERICAN MOTORS
1967-1993 BUICK
1976-1982 CADILLAC

So there should be plenty of those here.

Seriously considering doing the electric fan mod using Mustang parts as well. A guy in the US has done it and he claims his mpg went from 11.5 to 13.4mpg. That's nearly a 17% increase!

[Chubbs878]

there is an open thread on another site. member was asking for a scrap intake manifold so that he could modify it to accept the stat right at the outlet. Its being worked on but no solution as of yet. The LR water outlet pipe has either 1 more or 1 less fastener than a typical GM stat housing. I was wanting to run the top hose right over to the driver side but its impossible with the OEM LR manifold outlet pipe. Circumstances won't allow me the time or space to fabricate and market an improved version.

[Pedro_The_Swift]

Seriously considering doing the electric fan mod using Mustang parts as well. A guy in the US has done it and he claims his mpg went from 11.5 to 13.4mpg. That's nearly a 17% increase!

yea there is a single 17" elec that nearly fits,, but has he driven it through a creek yet? :angel:

[Battler]

I completed the inline stat a couple of days ago and I am very pleased with the result. I did the mod the same as Chubbs878 except for the top part.

https://www.aulro.com/afvb/

I used a 180c thermostat I ordered from from the USA but unfortunately it didn't work. No idea why other than it was a fancy super flow one. So I bought a Tridon 180c for $14 from Supacheap and that did the trick. My temps now are around 85c driving around town.

The advantages of this mod are:

1) temps are significantly lower but not too low (hasn't gone below 81c)
2) you can change the thermostat in under 2 minutes with minimal to no loss of coolant
3) thermostat is cheap to replace and can be found anywhere

So far no disadvantages

Cheers

[ozscott]

Nice Job mate. I take the points about easy and cheap replacement of the Stat.

As for the temp it is interesting. Mine with the low temp stat (stock set up otherwise) runs around town at 85 degrees and if idling in this weather for a while 87 degrees. I had it offroad clibming up to 3000 feet recently at GVM all low range stuff and it was always around 85-87 degrees.

I am very keen to see your temps when summer hits, but also with towing etc. If you are sitting on say 85-88 or so even when towing and in summer then I will probably do the mod (in summer mine didnt go higher than 94 from memory in heavy traffic and idling on a very hot Brissy day but if it could stay under 90 all the time that woud be great!!).

Cheers

[gavinwibrow]

So, without reading the whole thread, is this mod peculiar to V8s or should it also work on a diesel eg TD5 that gets too hot towing a large/heavy van?

[Battler]

Nice Job mate. I take the points about easy and cheap replacement of the Stat.

As for the temp it is interesting. Mine with the low temp stat (stock set up otherwise) runs around town at 85 degrees and if idling in this weather for a while 87 degrees. I had it offroad clibming up to 3000 feet recently at GVM all low range stuff and it was always around 85-87 degrees.

I am very keen to see your temps when summer hits, but also with towing etc. If you are sitting on say 85-88 or so even when towing and in summer then I will probably do the mod (in summer mine didnt go higher than 94 from memory in heavy traffic and idling on a very hot Brissy day but if it could stay under 90 all the time that woud be great!!).

Cheers

Thanks Ozscott, Yes, summer will be the big test. However, if I need to run cooler in summer I just need to spend $14 and get a 170 or a 160 thermostat.

My temps before the mod were 90 - 92 around town and if idling in traffic on a hot day sometimes it would go up to as high as 105. And that's what prompted me to do the mod.

Cheers

[Battler]

So, without reading the whole thread, is this mod peculiar to V8s or should it also work on a diesel eg TD5 that gets too hot towing a large/heavy van?

It's for the V8 but I can't see why you couldn't do it to a TD5.

[ozscott]

Hi Battler,

Yes 105 is too hot.

Mate this is a post I did from the thermostat thread

"...My 82 degree thermostat copped a work out today. 38 degrees outside and 67 degree intake temp. I gave it a hard time then idled it for a while and allowed temp to top out at 94. Later on heavy traffic at 39 degrees outside the coolant reached 95. AC going flat out at all times.

I reckon these temps are still sound. With the 4.0 running a stock stat it was 104-105 in the same conditions.

Cheers"

The stock stat does have them running too hot. I am happy at the moment with the engine because it has such a small temp fluctuation with the cooler stat and in very hot weather the max temp is acceptable to me at 94/95.

Cheers

[clubagreenie]

So glad I did not happen across this earlier in the discussion. WOW some people have little respect for others experience and knowledge.

FWIW:
There are two OEM bypass thermostats for the D2.
V8 & Diesel.
Different temps, same bypass spring tension.

The Freelander thermostat has both a lower temp and softer spring.

From first hand experience and hours of bench testing, with the Freelander 82 degree soft spring thermostat my 4.6 will sit on 87.7 degrees in city running, maybe get to 92 in summer stopped in traffic and highway running 85 degrees.

I've dealt with many from the states who have done the in line mod, well before our ranter has, with varying degrees of success. Several have gone back using the freelander thermostat and not looked back.

In essence, everyone will end up with a preference. But attitude is everything when trying to convince others of the worthiness and quality of a concept. Proven or not.

[ozscott]

Sorry but I totally disagree. I've been doing a lot of research and testing on these to find the best solution, and I'm a total convert to the Pressure Relief Thermostat (PRT) system.

What I have learned though extensive reading and testing, is that I had totally misunderstood (for years!) how the system works and the benefits it gives.

I have run engines covered in thermocouples to find out what goes on inside it, and it's quite a different story to what you see at the coolant outlet on the manifold.

The PRT bypass port is closed by the thermostat as it opens. What it does do is to stabilise the block temperature, as the water inlet to the pump is blended. Without it, the block temperature goes up and down by several degrees as the thermostat opens and closes. It is far more stable with a PRT, which reduces thermal stress between the block and liners.

In the case of the old thermostat in the top hose (which has served very well for over fifty years), there is also only one place for the water to go when the thermostat is closed. Of course that is the heater, which has to take the full flow. With the PRT there is the bypass circuit as well, which is fully available when the thermostat is closed.

When the thermostat opens, water is blended (hot with cold from the radiator) before being fed back to the engine. Because the bypass is open the flow is much faster through the engine block and head, so the temperature of the water coming down the bypass much more accurately reflects the block temperature.

Originally this system was developed to stabilise the temperature in smaller engines, with Cast Iron Wet Liners seated in Aluminium alloy cylinder blocks. The reason a stable temperature was required was that the rapid increases and drops in the temperature around the cylinder liners would cause them to un-seat from the block, and lead to leaks around the base of the liner seat and early head gasket failure.

I have measured this in some cases with a four cylinder engine, and found that in typical conditions the thermostat outlet temperature drops by 2-3 degrees after the thermostat opens, but it has taken some time for the cold water from the radiator to go through the water pump and all around the block to reach the thermostat. Where the water enters the block, the temperature will vary by 8-12 degrees (Centigrade of course). With a PRT, the temperature is stable throughout within 1-2 Degrees.

Although I cannot find any proof of this, I believe the principle was developed by Honda (I may be very wrong with that), as they were amongst the first to use this type of system. Since then, nearly every modern production car uses this system; partly for emissions, partly for longevity.

PRTs crossed from Honda to Rover (with the introduction of the K-Series engine), and then on to Land Rover. All Land Rover V8s since the arrival of the Disco 2 have used this system, as do Jaguar, BMW, etc.

We all know that car manufacturers are a tight bunch, and won't put anything there unless it's absolutely required. PRTs cost more, so there must be a reason.

As far as I can see, the only challenge with the PRT is the massive lack of choice of opening temperatures. All European Disco 2 and Range Rover P38 V8 motors came with a 92 'stat, which means they run at 95-96 degrees normally.

Whilst there was an 82 Degree hot climate 'stat available for the D2, it has long since been obsolete. This would have given an operating temperature of 85 Degrees, which is pretty much ideal for a road-going V8. I have recently bought loads of different 'stats (many advertised as 82 Degree) to test, but most of them have turned out to be 87 Degree. Nonetheless, that gives an operating temperature of 90 Degrees, which is still better than 95 Degrees. Tomorrow I am testing yet another 82 Degree version, and I have high hopes for this one. Of course I'll let you know what I find.

Out of interest, 95 Degrees is the point at which the Rover V8 starts to lose power. The difference between 95-102 Degrees is around 15 BHP lost. Heat is also a factor in facilitating the dreaded slipped liner.

I'm in the process of converting all my top-thermostat V8s to PRTs, and the results look very good so far.

However, I always have an open mind... ;)

Hi Mark - how did you go with the further testing for the thermostat?

Cheers

[ozscott]

OK I am sick of the cooling system of the D2. It is overengineered and probably never a good thing. My hoses are rock hard when running and at normal operating temp. Inline stat in and...normal pressure has been restored to the hoses. My mechanic and I will experiment with best positioning etc.

Cheers

[CU55TM Disco]

+1 for the Freelander OEM thermostat here, TD5 auto.

everyday temp 87 degrees, regardless of traffic, highway cruising or pottering around town. towing i see 92, not a degree more, and thats comming back from sydney on a warm spring day with a dualcab courier on a rental trailer.

obvoiusly right foot plays a fair part in regulating ur temps also, i dont particularly want to break my td5, so I treat it with respect.

[Barefoot Dave]

G 'day fellas.
What year/engine FL thermostat is that?

[ozscott]

OK here is the mock-up for testing. 88 degree stat. Highway is 85_87 on a 30 degree day and running around in traffic in town on a 33 degree day (today) was 84_87. Pressure in top hose is evident but not rock hard like the 3 way stock thermostat with shut off idle valve choking things. At idle after a hard run at home 33 degrees outside temp and after 15mins of idling she stayed at Max 88 degree C. See photo of intake temp too... 60 degrees C...

The only thing is that we put on a Britpart viscous coupling and the bloody thing is very aggressive. If I accelerate on the highway in 4th when the coolant is 84 it still blows at full noise... It is only off when the engine is dead cold! I don't think it will stay. It may raise running temps slightly if I go back to a stock viscous coupling. Cheers
https://www.aulro.com/afvb/images/imported/2016/10/647.jpghttps://www.aulro.com/afvb/images/imported/2016/10/648.jpghttps://www.aulro.com/afvb/images/imported/2016/10/649.jpg

[ozscott]

Thermostat needs to be as close to motor as possible. D1 had fitting in front and top of motor. Need small bleed hole in stat flange for sensing also. Cheers

[ozscott]

Ok with just water for testing 81-82 around Brisbane today and genuine LR viscous unit in so no crazy fan noises ! I think we might be on a winner to keep engine and cooling system happy finally. Cheers

[ozscott]

OK so it has settled at 82_85 on a 26 degree day in traffic and 85 on the highway at 100-110 in the same outside temp. I am Much more comfortable with that than the stock temps. This mod allows better highway temps too than compared to the cooler 3 way LR stat I put in... Which makes sense because at its best the 3 way blends 10 per cent hot block coolant back into the block with the 90 per cent cooler water from the rad... Cheers

[Mumfy1973]

I completed the inline stat a couple of days ago and I am very pleased with the result. I did the mod the same as Chubbs878 except for the top part.

http://www.efq.com.au/In-Line-Stat-Mod-D2.JPG

I used a 180c thermostat I ordered from from the USA but unfortunately it didn't work. No idea why other than it was a fancy super flow one. So I bought a Tridon 180c for $14 from Supacheap and that did the trick. My temps now are around 85c driving around town.

The advantages of this mod are:

1) temps are significantly lower but not too low (hasn't gone below 81c)
2) you can change the thermostat in under 2 minutes with minimal to no loss of coolant
3) thermostat is cheap to replace and can be found anywhere

So far no disadvantages

Cheers

Where did the housing come from

[ozscott]

Overseas for mine. Not cheap buy hey cheaper than an LR stat by a long way and cheaper than a motor...

Cheers

[Battler]

I got mine from JEGS in the USA.

[clubagreenie]

I hope you mean 180f not c

[Battler]

Yep, should be 180f and not 180c.

Thanks for pointing it out.

Cheers

[ozscott]

Going to put in the low water Engine Saver tomorrow. Got a bit of 35mm brass pipe brazed up with end barbs and tapered threaded fitting to host the nylon nut and stainless bolt. All painted black so should blend I well. I will probably leave the Freelander top hose on as it works well enough I think. Will flush it all and put in (super) long life Nulon green HOAT and will post some photos and report back. Cheers

[ozscott]

OK originally had just thermostat and couldn't get air out. So this is the second version. Very happy with it. Bleeds air out and thermo still responds quickly. Cruising around today 85 highway and around city. Cheers 1156331156341156351

[lewy]

Could you use the JEGS Performance Products 51155: Inline Hose Drain 1.5" | JEGS (http://www.jegs.com/i/JEGS-Performance-Products/555/51155/10002/-1) turned upside down for the low water alarm,looks like the drain just screws out..Just trying to get off the shelf stuff as much as possible.

[Pedro_The_Swift]

wow thats ugly,, way too many clamps for my "each one is a possible leak" mind...
I have no doubt it works, but---

then again I suppose you've gotten rid of a couple:p

[Battler]

Could you use the JEGS Performance Products 51155: Inline Hose Drain 1.5" | JEGS (http://www.jegs.com/i/JEGS-Performance-Products/555/51155/10002/-1) turned upside down for the low water alarm,looks like the drain just screws out..Just trying to get off the shelf stuff as much as possible.

That's what I used for my installation but without the low water alarm.

[ozscott]

Haha. It's all visible and I like an Ozzy made Tridon... Plus beauty is in the eye. I quite like the custom look. 30 degrees out and after a hard run accelerating in inner city traffic coolant at idle settles at 90 degrees with intake air temp at 56 degrees.... I think 50/50 coolant water mix makes for a much higher (132 degree - Nulon) boiling point but doesn't actually get rid of heat as well as a lower mix ratio. Cheers 115725

[ozscott]

On my count I am on exactly the same number of clamps... Just that I can now see them and they are good clamps not the silly stock LR ones. Cheers

[DieSchnelleKafer]

I'll provide my experience with the inline mod. with a stock system i used to see operating temps from roughly 94-100 degrees.

After my 80 degree thermostat mod i will fluctuate between 80 to 84 degrees. Stock viscous unit.

I have driven both systems in the winter and on 40 degree days.

https://www.aulro.com/afvb/images/imported/2017/01/870.jpg (http://s50.photobucket.com/user/BlairWhittle/media/DSCN2039_zpsbdzkg7w4.jpg.html)

https://www.aulro.com/afvb/images/imported/2017/01/871.jpg (http://s50.photobucket.com/user/BlairWhittle/media/DSCN2040_zpsjreu0luk.jpg.html)

[ozscott]

Mate that looks good but the thermostat is a long way from the block. I also think the concerns about some people on here about the radiator water getting very cold in winter and then being suddenly pushed into a hot blocked are well founded. I'm going back to a low C 3 way LR setup that blends and avoids sudden cold shock to the block.

Cheers

[Geoff86RRC]

As discussed I have had the inline mod done with an 82c stat and drilled hole. This allows a limited amount of water to circulate in radiator (but) slows rise to op temp. In colder weather it assists the radiator by allowing a limited trickle of water at all times to circulate, which is probably "too much" cooling and keeps the stat closed. But it stops cold shock. That is critical.
I am in Brisbane which is hotter rather than colder so in Autumn and Spring am going to swap to an 87c and 82c stat respectively.
I agree the Heavy Duty viscous fan is too noisy.
I had intended to swap to the softer spring freelander thermostat, as I respectfully and without too much knowledge nonetheless believe that the softer spring will allow this engine when it is only at idle to have the benefit of a radiator in the circuit, as the softer spring will allow the bypass to close, and send the water through the radiator.
When I still had the OEM stat it would rise to 105c at idle. In addition it would spike at speed.
I cut my old stat open and tested it in water. It opened like a bought one at 93c. I can only think the bypass spring was too hard
I just did a climb to Killarney 500 m from sea level, via Teviot Brook, and although it was an 18c day, the temperature never rose above 86 to 87.

Whatever works for you keep those temps down.
Cheers and thanks for all the very valuable posts.

Geoff
D2 2000 v8
2A SWB gone
75, 75, 85, 89 RRC gone

[DieSchnelleKafer]

Mate that looks good but the thermostat is a long way from the block. I also think the concerns about some people on here about the radiator water getting very cold in winter and then being suddenly pushed into a hot blocked are well founded. I'm going back to a low C 3 way LR setup that blends and avoids sudden cold shock to the block.

Cheers

I think you will find that the water temperature between the block outlet and the thermostat will not drop in temperature enough to effect the opening and closing of the thermostat. Rubber is not a very good conductor of heat to atmosphere, and because i have drilled a relief hole at the top of the thermostat disc itself, there is always water circulating through the system. This prolongs warm up time i admit, but from what i see it inhibits temperature fluctuations. For the way i have set my system up, it works well for me :D

[ozscott]

I suppose we go back to Disco 1 and RRC...they had a dead head thermostat in the motor...so they would be subject to the same cold water going into a hot block when the thermostat opened...but they did not have anything like the same problems at D2 V8's...

Cheers

[Geoff86RRC]

Our modified in line thermostat, which has a small but absolutely crucial bleed hole drilled in it, changes the system from a true dead head (where the discharge side of the pump is completely dead due to being blocked by a thermostat closed due to low temperature) to a not completely dead head system as there is a permissible flow of water. As discussed, this stops the hot/cold water column problems which can occur when the thermostat finally opens as the water column from the block reaches opening temperature (82c 87c 93c or whatever) and results in the circuit fully opening, relatively quickly. This allows cold ambient temperature water from the bottom of the radiator returning in through the bottom of the engine to be pushed up through the engine, resulting in a potential chill to an otherwise hot block. There is as always, a price to be paid, and that is that the engine takes longer to reach operating temperature due to the permitted bleed. In Brisbane (27S), during day driving, in summer, daylight temperatures are usually above 15c and are usually up above 30c. In these conditions, the small delay in reaching operating temperature is not critical. I accept that in colder climates one may need to run a hotter temperature thermostat to keep the engine up at operating temperature. From my reading of many posts now about this, I discern that a lot of the rationale for that bypass system was actually for occupants' comfort in relatively cold weather, by enabling the heater to "work quickly". It also makes the engine more efficient. Because it was colder, the engine could reach and stay at operating temperature quickly, heat the cabin and use the radiator when needed. Thus the bypass is feeding the heater matrix in preference to the radiator. Given that the heating system is a small radiator, it makes sense that again, in very cold weather, the heater would be cooling the engine water temperature, as well as the ambient temperature being very low. So for instance in a 2c environment, a heater operating at 18c or 20c, would be cooling the engine significantly. In hotter parts, this is simply not indicated and poses a real and sadly too often seen as a catastrophic failure.
Scott, I agree with respect. I would be very interested to research the catastrophic failure rates in subtropical and tropical climates. I am in touch with Foleys out in Zambia so will ask them.

[ozscott]

Mate Murray has a growing table of 3 way stock thermostats and a bench top with brass connectors to take the place of the 3 way. He is changing a lot over now. Cheers

[Geoff86RRC]

An explanation from the manual: with my comments/conjecture
General
The cooling system used on the V8 engine is a pressure relief by-pass type system which allows coolant to circulate around the cylinder block and the heater circuit when the thermostat is closed. With coolant not passing through the radiator, this promotes faster heater warm-up which in turn improves passenger comfort. [This is not needed in hot climes] A coolant pump is located in a housing at the front of the engine and is driven by a drive belt. The pump is connected into the coolant passages cast in the cylinder block and pumps coolant from the radiator through the cylinder block. [when the thermostat is open ] A viscous fan is attached by means of a nut to the coolant pump pulley drive spindle. The fan draws air through the radiator to assist in cooling when the vehicle is stationary. The fan rotational speed is controlled relative to the running temperature of the engine by a thermostatic valve regulated by a bi-metallic coil. The cooling system uses a 50/50 mix of anti-freeze and water.

Thermostat housing
A plastic thermostat housing is located behind the radiator. The housing has three connections which locate the radiator bottom hose, top hose [return from the engine, pushed out by the water pump] and coolant pump feed hose [Used by the pump to suck water up to the pump]. The housing contains a wax element and a spring loaded by-pass flow valve. The offset side top pipe goes to the pump through which water is pulled. The top straight up one is one inlet to the stat and is hot water exiting from from the engine, coming to the stat as an alternative to going to the radiator thanks to the T junction and a closed stat. This upper chamber forms the non radiator circuit when stat is closed. The four sensing holes in a brass "bypass valve" see below allow hot engine water to be drawn into this upper chamber at idle. At higher revs the upper light spring opens and allows a greater flow round this bypass system. NB at this stage the radiator is not used until the main temperature based thermostat valve opens, allowing cool radiator water to be sucked into the lower entry pipe.

Thermostat - Main valve
The thermostat is used to maintain the coolant at the optimum temperature for efficient combustion and to aid engine
warm-upin the UK conditions as interpreted by BMW...the 3500s did 500,000 miles if serviced with a simple in line stat. Sure, heater might take longer to fire up but the engines would not blow! Now that I reflect upon it, I see lots of old Rovers and Land Rovers but no old BMWs...!. The thermostat is closed at temperatures below approximately 82 C (179 F). When the coolant temperature reaches approximately 82 C the thermostat starts to open [mine did not start to open until 93C. The radiator circuit relies on the pump sucking water through the side top tube through a now open stat at a greater flow than it just circulating through the bypass circuit. Now if, and this is conjecture, the radiator water coming into the bottom or lower lower chamber of the stat housing is too cold it May be causing the thermostat to not fully open. As soon as revs drop off ie idling in traffic, the "light spring" top by-pass flow valve closes, see below, there is less hot water entering the upper chamber, and cold radiator water entering the lower, and I submit this closes the stat, and most water then just circuits in the heater matrix circuit. and is fully open at approximately 96 C (204 F). In this condition the full flow of coolant is directed through the radiator. [I am not understanding how it is "directed" around the radiator circuit if the is an equal diameter though arguably restricted bypass circuit. The thermostat is exposed to 90% hot coolant from the engine on one side and 10% cold coolant returning from the radiator bottom hose on the other side. Hot coolant from the engine passes from the by-pass pipe through four sensing holes* in the flow valve into a tube surrounding 90% of the thermostat sensitive area. Cold coolant returning from the engine[no-if it's from the engine its hot. Only from the radiator is it cold. , cooled by the radiator, conducts through 10% of the sensitive area. In cold ambient temperatures, the engine temperature is raised by approximately 10 C (50 F) to compensate for the heat loss of 10% exposure to the cold coolant returning from the bottom hose. [I do not understand this? How?
*The sensing holes in mine may have been partially blocked by the stop leak put into the system?? And scale. This would especially at idle allow the by-pass flow valve to block hot water from the engine trying to enter the 93c thermostat in the upper chamber. This would keep the stat fully or partially closed and overheat the engine by sending it all through the heater matrix especially at idle

By-pass flow valve
The by-pass flow valve is held closed by a light spring.[Freelander is lighter still. It operates to further aid heater warm-up. When the main valve is closed and the engine speed is at idle, the coolant pump does not produce sufficient flow and pressure to open the valve. In this condition the valve prevents coolant circulating through the by-pass circuit and forces the coolant through the heater matrix only. This provides a higher flow of coolant through the heater matrix to improve passenger comfort in cold conditions. [I cannot remember when I last used the heater in Brisbane! My engine was always hot hot hot. The previous owner had a catastrophic failure. I nearly did when a heater hose cracked and I heard the hissing ...just dumb luck and GOD. When the engine speed increases above idle the coolant pump produces a greater flow and pressure than the heater circuit can take. The pressure acts on the flow valve and overcomes the valve spring pressure, opening the valve and limiting the pressure in the heater circuit. The valve modulates to provide maximum coolant flow through the heater matrix and yet allowing excess coolant to flow into the by-pass circuit to provide the engine's cooling needs at higher engine rev/minute.[Herein is the problem I suspect. This system ie the upper bypass circuit in my vehicle has clearly been working in preference to the radiator circuit (in to the stat housing from cold bottom of radiator up through the lower single pipe through an open stat and out the side upper pipe to the pump then back out of the engine HOT and to the top hose, ignoring the by-pass circuit by turning 90 degrees at the top T junction and into the top of the radiator to work down, get cooled and leave by the bottom radiator hose. No. The upper chamber on a new stat was stained from coolant but not the lower. For some reason the system was favouring the upper by-pass circuit My vehicle's overheating got much worse after a new radiator was installed. I pose the question: Could the new rad actually be cooling the water to such an extent that the cold water in the base of the stat caused it to not or only partially open?

http://http://workshop-manuals.com/landrover/discovery-ii/cooling_system_v8/description_and_operation/description/page_503/ (http://workshop-manuals.com/landrover/discovery-ii/cooling_system_v8/description_and_operation/description/page_503/)

[Geoff86RRC]

Mate Murray has a growing table of 3 way stock thermostats and a bench top with brass connectors to take the place of the 3 way. He is changing a lot over now. Cheers

I know Scott! Thanks for your great help! He is also working on a really cheap efficient temp gauge that's easy to read and works from the sender or another sender.
I have engine watchdog which is 3 to 4, degrees cooler but has a screamer for the wife to hear.
I also have OBDC wireless and OBDC fusion which is great.
Here is a screen shot of the return from Boonah ambient circa 16 C
Unheard of temp is on right

[nismine01]

Boy are there some theories in this thread, some backed up with data.

I was told by a DII owner mechanic and workshop owner to go easy with the OAT concentrate coolant, "It will find it's way out anywhere". To that point a set of hoses bought from a reliable supplier on this site bled coolant through the cordage within the hoses after a very short time. My 'new' current TD5 has the same problem, there is evidence of coolant leaks at most hoses and upon closer inspection it has bled through the cord within the hose.

I have always believed in the 'Oils ain't oils' brand of coolant, the Army used it and I figure if it's good enough for them to use, it's good enough for me, but with my Landys I have stuck with OAT. No more, when I change my hoses over I will change my coolant, with all the necessary precautions of not mixing the two.

On the temperature side, I have run the vehicle with my Nanocom hooked up and the temperature has fluctuated depending on what is going on outside, down hill drop back to 85ish pulling up a hill way past 110 and that is at a constant speed.

An argument put in this thread is that the original thermostat set up will keep a more even temperature in the system. From my observation this is not so.

I am going to set up my 2003 TD5 Disco with the simplest of systems and a thermostat in the top hose seems the way to go.

I also want to try find silicone hoses that will do the job with the least number of joints. Another thing about clamps, I always try put them on so I can get them off on the roadside if I have to, the mechanic who put them on this car did it before the radiator went in so all the clamps were in impossible spots to get to without a great deal of trouble (that seems to be my middle name, but it still hurts).

I think the thermostat needs to be after the heater take off and I wonder why there can not be a bleed off (where the air bleed is) that constantly bleeds into the radiator bleed off, I thought that was what that is there for, what other purpose can it have?

If it is possible to not have a high point where air can get trapped could I do away with the air bleed screw?

Just have to make sure that the fuel cooler gets fed somehow.

Argh, already my head hurts.

Cheers

Mike

[Mark Adams]

How about this bad boy, that allows you to choose the operating temperature you require?

It's just a prototype for now, but will be undergoing fully instrumented testing on the engine...

https://www.facebook.com/tornadosystems/photos/pcb.1212969298781469/1212958748782524/'type=3&theater

[ballbag]

Nice.

[ozscott]

If it still blends at least 10% hot water from the block it is still a compromise. I don't see from the photo text how it works. Great looking though. Mark can you elaborate? Thanks for continuing great product development for D2.

Just an interesting thing to remember. If you think your fan hub is suspect it may not be activating, but may be fine. It relies on radiant heat from the radiator to activate - and will lag if the radiator is not heating up properly due to being blocked. I noticed when I put my new radiator in (old heavily blocked) that suddenly I am hearing my clutch fan a lot more.

Cheers

[Geoff86RRC]

If it still blends at least 10% hot water from the block it is still a compromise. I don't see from the photo text how it works. Great looking though. Mark can you elaborate? Thanks for continuing great product development for D2.

Just an interesting thing to remember. If you think your fan hub is suspect it may not be activating, but may be fine. It relies on radiant heat from the radiator to activate - and will lag if the radiator is not heating up properly due to being blocked. I noticed when I put my new radiator in (old heavily blocked) that suddenly I am hearing my clutch fan a lot more.

Cheers

It's just the same as OEM but allows a hotter or cooler stat to be swapped out

[Mark Adams]

It's just the same as OEM but allows a hotter or cooler stat to be swapped out

Absolutely right! We have just found it impossible to get an 82 Degree thermostat still in production that works correctly. A suitable stock one would definitely be the cheaper way to go. Sadly the "Hot Climates" 82 Degree version offered by Land Rover has long since been obsolete.

There is one very well known brand available, but it has a fatal flaw in the design that leads to operating temperatures way above the 82 degrees that the thermostat opens at. Obviously I can't say who makes it here, but the design flaw is that the bypass is fully closed with significant spring pressure even when the thermostat is closed.

As we have tested quite a few different thermostats, this is the one that gave the most scary behavior. When it was installed for the first time, the engine got up to 118 Degrees C before the thermostat finally opened! I was just about to terminate the test, but it did eventually open. This is despite the thermostat inside starting to open at a genuine 82 Degrees, as we chopped it up to get the thermostat out for testing.

We tested another identical one from the same manufacturer to make sure it was not a one-off, as it is always dangerous to base your conclusions on a sample of one!

In operation, it ran at 95-97 degrees, and when idling in traffic on a hot day (only 35 Degrees, but hot by UK standards!) with the AC on the temperature went up to 115 Degrees easily. All in all, a great way to kill your motor.

Note that absolutely all the stock Rover V8 cooling systems allow some bypass of the main radiator via the heater circuit. The amount of resistance to the thermostat bypass relative to the heater circuit is a critical factor in determining how well the thermostat reacts to the rise in temperature, and the rate at which it opens.

It is quite possible that with this type of PRT thermostat that the heater circuit could be eliminated on competition vehicles, or any other vehicles that will never need the heater. More testing is required first though.

Before this thermostat reaches the point of sale, it will be run through some very demanding scenarios on an engine dyno. This allows it to be fully instrumented for temperature and pressure. I used to have a lot of data for these tests, but sadly https://www.aulro.com/afvb/images/imported/2017/02/548.jpgit got lost in a house move a long time ago. Anything we do is based on science with documented results, and this will be no exception.

https://www.aulro.com/afvb/images/imported/2017/02/548.jpg