new radiator for TD5, please explain

[bob10]

Before the wife retires, & we go for a long drive, one of the things I would like to do is refurbish the cooling system. Apart from the hoses etc, with 364,000 kms on the clock, a new radiator might be in order. I have been looking, one mob has this spiel to go with their new radiator, not sure what to make of it, I thought it would have been just a simple swap. I have a 1999 [ although vin check says it is 2000] model TD5, cheers, Bob

This is a new Radiator to suit Discovery 2 TD5 5 cylinder diesel 1999-2004. The core of this radiator measures 440mm in height and 590mm in length.
When fitting a new TD5 Discovery radiator you need to fit a fuel cooler restrictor (part no. PCS000010), to restrict the flow of the water/coolant. This restrictor fits into the front end of the fuel cooler which is underneath the inlet manifold on the driver's side. The new radiator will have no holes at the bottom, they are blanked off. The hoses go back onto these blanking plugs the same as they came off the old radiator.

[alien]

The lower section of the radiator has a separate section for cooling the water from the fuel cooler.
It appears from reading the blurb the new radiator doesn't have this feature.
To get around it they offer the restrictor to connect the fuel cooler hoses to.

I bought a radiator via this forum and drilled the blanked sections out as barbs where fitted for hoses.
I expect on the new one your looking at this can't be done.

Do you have a link or picture to confirm?

[OffTrack]

Before the wife retires, & we go for a long drive, one of the things I would like to do is refurbish the cooling system. Apart from the hoses etc, with 364,000 kms on the clock, a new radiator might be in order. I have been looking, one mob has this spiel to go with their new radiator, not sure what to make of it, I thought it would have been just a simple swap. I have a 1999 [ although vin check says it is 2000] model TD5, cheers, Bob

This is a new Radiator to suit Discovery 2 TD5 5 cylinder diesel 1999-2004. The core of this radiator measures 440mm in height and 590mm in length.
When fitting a new TD5 Discovery radiator you need to fit a fuel cooler restrictor (part no. PCS000010), to restrict the flow of the water/coolant. This restrictor fits into the front end of the fuel cooler which is underneath the inlet manifold on the driver's side. The new radiator will have no holes at the bottom, they are blanked off. The hoses go back onto these blanking plugs the same as they came off the old radiator.



Radiator design was changed in 2002. The quote describes the part you need when using one of the new spec radiators on vehicles built prior to 2A736340.

Tech bulletin describing the change and implications attached.

cheers
Paul

[bob10]

The lower section of the radiator has a separate section for cooling the water from the fuel cooler.
It appears from reading the blurb the new radiator doesn't have this feature.
To get around it they offer the restrictor to connect the fuel cooler hoses to.

I bought a radiator via this forum and drilled the blanked sections out as barbs where fitted for hoses.
I expect on the new one your looking at this can't be done.

Do you have a link or picture to confirm?

Here is a photo.
https://www.aulro.com/afvb/images/imported/2013/09/847.jpg

What I find difficult to understand is, the two spigots are there, and looking at the drawing " COOLING SYSTEM - TD5 , Cooling system coolant flow", from RAVE, the restrictor is placed in the inlet side of the fuel cooler, coming from the bottom spigot on the radiator. Coolant from the OIL cooler outlet, via the secret hose, around the back of the engine, flows to the radiator via the top spigot. If those spigots are blanked off, surely that adversely effects coolant flow. No doubt LR engineers have engineered a solution, but what? Is there an upgraded drawing? Bob

[northiam]

I drilled the blank spigot (small hole) as I figured to have a pipe blanked from the oil cooler dead and unable to purge the air could not be a good thing.
Why not blank off oil cooler outlet and delete the pipe completely.
I did not fit restrictor maybe I should...
Regards

[mrjc]

Good morning bob 10,i recently bought and fitted a new radiator to my 99 d2 td5 the radiator i got (of ebay) there's no drilling or anything it seemed to be straight swap over,nice and easy job only took about 1/2 the day cleaned out the intercooler while it was out and replace the intercooler pipes as well, i did mine with the fan still in but would of been a lot easier if it was removed.
1 Radiator Landrover Discovery Series 2 II TD5 Auto Manual '99 '04 Turbo Diesel | eBay (http://www.ebay.com.au/itm/1-Radiator-Landrover-Discovery-Series-2-II-TD5-AUTO-MANUAL-99-04-Turbo-Diesel-/231028554641?pt=AU_Car_Parts_Accessories&fits=Make%3ALand%20Rover%7CModel%3ADiscovery&hash=item35ca5ffb91&_uhb=1)

[bob10]

I drilled the blank spigot (small hole) as I figured to have a pipe blanked from the oil cooler dead and unable to purge the air could not be a good thing.
Why not blank off oil cooler outlet and delete the pipe completely.
I did not fit restrictor maybe I should...
Regards

I've been reading the cooling system description in RAVE, trying to understand the system, bit of a slog. There are two conflicting statements, regarding the oil cooler return pipe.
From " the cooling system TD5";

1. Oil cooler

The oil cooler is located on the left hand side of the engine block behind the oil centrifuge & oil filter. Oil from the oil pump is passed thru a heat exchanger which is surrounded by coolant in a housing on the side of the engine. Full water pump flow is directed along the cooler housing which also distributes the flow evenly along the block into 3 core holes for cylinder cooling. this cools the engine oil before it is passed into the engine. A small percentage of the coolant from the oil cooler passes into a metal pipe behind the engine.[ via the secret hose] It then flows into the lower radiator via a hose.

2. From " engine TD5 "

Coolant flow circulates thru the oil cooler housing under pressure from the coolant pump & distributes the flow evenly around the matrix fins & then along the block into 3 core holes for cylinder cooling. Coolant enters the oil cooler through a pipe with a rubber hose extension at the rear side of the engine [ secret hose] I believe this statement to be incorrect, & statement 1 to be correct. If you look at Offtracks post of the technical bulletin, [bottom of page]you will see the top spigot is blanked off, the bottom one seems to have a small orifice to allow some water flow to the fuel cooler. I am assuming the new radiators do not have the 4 pass section in the bottom for the fuel cooler as the original ones do, & therefore you would be getting full water pump pressure at the inlet of the fuel cooler. So, what have I got out of this besides a headache, and the need for a cleansing ale?

Coolant flow to the oil cooler comes direct from the water pump, thru the engine jacket, to the oil cooler , into the pistons & out the outlet housing to the top of the radiator. So blanking off the top spigot should not effect the flow of coolant to the oil cooler. As a matter of fact, I don't see a reason to have that secret hose at all, if I am correct.

Full water pump pressure is pumped thru the small orifice in the bottom spigot to the inlet of the fuel cooler, so yes, you must fit the restrictor. Of course, I'm hoping the original radiator is still available, but if not I'm happy to replace it with the new one. My head hurts, what time does the footy club open? Bob PS, don't drill the blanked holes at the bottom of the radiator


https://www.aulro.com/afvb/images/imported/2014/01/24.jpgL8711bu.pdf (http://www.aulro.com/afvb/attachments/discovery-2/65663d1379320504-new-radiator-td5-please-explain-l8711bu.pdf) (770.4 KB, 27 views)

[bob10]

Good morning bob 10,i recently bought and fitted a new radiator to my 99 d2 td5 the radiator i got (of ebay) there's no drilling or anything it seemed to be straight swap over,nice and easy job only took about 1/2 the day cleaned out the intercooler while it was out and replace the intercooler pipes as well, i did mine with the fan still in but would of been a lot easier if it was removed.
1 Radiator Landrover Discovery Series 2 II TD5 Auto Manual '99 '04 Turbo Diesel | eBay (http://www.ebay.com.au/itm/1-Radiator-Landrover-Discovery-Series-2-II-TD5-AUTO-MANUAL-99-04-Turbo-Diesel-/231028554641?pt=AU_Car_Parts_Accessories&fits=Make%3ALand%20Rover%7CModel%3ADiscovery&hash=item35ca5ffb91&_uhb=1)

Thanks for that, what did you use to clean your intercooler? Bob

[mrjc]

Good morning bob 10,i recently bought and fitted a new radiator to my 99 d2 td5 the radiator i got (of ebay) there's no drilling or anything it seemed to be straight swap over,nice and easy job only took about 1/2 the day cleaned out the intercooler while it was out and replace the intercooler pipes as well, i did mine with the fan still in but would of been a lot easier if it was removed.
1 Radiator Landrover Discovery Series 2 II TD5 Auto Manual '99 '04 Turbo Diesel | eBay (http://www.ebay.com.au/itm/1-Radiator-Landrover-Discovery-Series-2-II-TD5-AUTO-MANUAL-99-04-Turbo-Diesel-/231028554641?pt=AU_Car_Parts_Accessories&fits=Make%3ALand%20Rover%7CModel%3ADiscovery&hash=item35ca5ffb91&_uhb=1)
Hi bob 10, i just used liquid and spray degreaser i bought from supercheap, just sprayed the outside and then filled it up with the liquid stuff(watered down) let it soak for about an hour then gave it a good rinse,left it dry in the sun for a couple of hours it was 29 that day so didn't take long,bob also take a quick look underneath your top radiator hose were the pipe that branches out and sits on top of the air con pipes is it has the mesh over it,these can rub through and leak as mine did i had to replace with a new one and cable tie this bit of pipe back so it didn't rub.

[northiam]

Good morning bob 10,i recently bought and fitted a new radiator to my 99 d2 td5 the radiator i got (of ebay) there's no drilling or anything it seemed to be straight swap over,nice and easy job only took about 1/2 the day cleaned out the intercooler while it was out and replace the intercooler pipes as well, i did mine with the fan still in but would of been a lot easier if it was removed.
1 Radiator Landrover Discovery Series 2 II TD5 Auto Manual '99 '04 Turbo Diesel | eBay (http://www.ebay.com.au/itm/1-Radiator-Landrover-Discovery-Series-2-II-TD5-AUTO-MANUAL-99-04-Turbo-Diesel-/231028554641?pt=AU_Car_Parts_Accessories&fits=Make%3ALand%20Rover%7CModel%3ADiscovery&hash=item35ca5ffb91&_uhb=1)


If your radiator is suited to a 99 to 04 discovery td5 then its has blanked off connections.:)

[Sunova]

Wow this is a confusing thread. It has got me praying that I didn't do the wrong thing for my TD5's radiator. I drilled out (by hand- slow and easy) the bottom outlet pipe. The old one had a hole so my reasoning and research stated drill out the new one. The restrictor talking about is to help bring the engine up to operating temperature quicker and in our climate I didn't think it was essential. I have had it like that for about 15,000km and no problems.

[bob10]

Wow this is a confusing thread. It has got me praying that I didn't do the wrong thing for my TD5's radiator. I drilled out (by hand- slow and easy) the bottom outlet pipe. The old one had a hole so my reasoning and research stated drill out the new one. The restrictor talking about is to help bring the engine up to operating temperature quicker and in our climate I didn't think it was essential. I have had it like that for about 15,000km and no problems.

I don't know the consequences of drilling out the spigots , but the tech bulletin did say this;



NOTE: The feed and return pipes, (.C. and .D. in illustrations 1 and 2), to the lower



section of the radiator have been modified. Do not attempt to open these coolant

passageways into the radiator.

[bob10]

The restrictor talking about is to help bring the engine up to operating temperature.
From what I have read, absolutely nothing to do with bringing the engine up to operating temperature. If you have RAVE, please read the relevant chapters. If not, get RAVE & do same. Hard going sometimes, but does explain the jigsaw puzzle that is the TD5 coolant system, Cheers, Bob

[alien]

Here is a photo.
https://www.aulro.com/afvb/images/imported/2013/09/847.jpg

What I find difficult to understand is, the two spigots are there, and looking at the drawing " COOLING SYSTEM - TD5 , Cooling system coolant flow", from RAVE, the restrictor is placed in the inlet side of the fuel cooler, coming from the bottom spigot on the radiator. Coolant from the OIL cooler outlet, via the secret hose, around the back of the engine, flows to the radiator via the top spigot. If those spigots are blanked off, surely that adversely effects coolant flow. No doubt LR engineers have engineered a solution, but what? Is there an upgraded drawing? Bob
Now you mention that no coolant could flow from the oil cooler if the spigot is blanked off it reminded me of something I read here maybe a year ago.
There was a member loosing coolant from a blanking rubber fitted where the secret hose goes.
He had no pipe around the rear of the motor and at the time many members thought it was odd.
Now I'm wondering if it had the upgraded radiator fitted and the un-needed parts removed.

[bob10]

Now you mention that no coolant could flow from the oil cooler if the spigot is blanked off it reminded me of something I read here maybe a year ago.
There was a member loosing coolant from a blanking rubber fitted where the secret hose goes.
He had no pipe around the rear of the motor and at the time many members thought it was odd.
Now I'm wondering if it had the upgraded radiator fitted and the un-needed parts removed.

I was one who thought it was odd, but I didn't have a clue about the coolant system on the TD5, still only know a little bit. I'm beginning to wonder if some of the overheating problems on the TD5 in Aus. has been caused by our [ especially our local mechanics] lack of knowledge about maintaining the engine. Just a thought, Bob

[bob10]

I think a description of the original radiator as per RAVE may help ,

Radiator

The 44 row , cross flow type radiator is manufactured from aluminium with moulded plastic end tanks interconnected with tubes. The bottom four rows are separate from the upper radiator and form the lower radiator for the fuel cooler. [ I believe the new, updated radiator mentioned in the Tech. bulletin does not have this separate section]

Two connections at the top of the radiator provide for the attachment of the top hose from the outlet housing and bleed pipe to the expansion tank. Three connections at the bottom of the radiator allow for the attachment of the bottom hose to the thermostat housing and the return hose from the oil cooler and feed hose to the fuel cooler.

The bottom four rows of the lower radiator are dedicated to the fuel cooler. The upper of the two connections at the bottom of the radiator receives the coolant from the oil cooler. This is fed through the four rows of the lower radiator in a dual pass and emerges at the lower connection. The dual pass lowers the coolant temp. by 24 degree C before being passed to the fuel cooler.

That is the original radiator, the modified one supplies coolant to the fuel cooler from the bottom spigot , thru a restriction, and I believe the separate bottom four row fuel cooler section has been done away with, because with the top spigot blanked, there would be no coolant flow to the fuel cooler. Exactly what happens if you drill out that blanking, I'm not sure. Bob

[Sunova]

I thought I had conducted appropriate research before I drilled out the blank outlet. My understanding is the EU3 models had the blank and the EU2 earlier models had an open port. I rang the supplier, googled my brain off and spoke to mechanics who said that the port should be opened. Hence the port being there if required and not just a single outlet on the radiator. The original radiator was open, but then the internal compartments could be different.

PS I am only a weekend mechanic, so there is a good chance I am wrong.

[alien]

I think a description of the original radiator as per RAVE may help ,

Radiator

The 44 row , cross flow type radiator is manufactured from aluminium with moulded plastic end tanks interconnected with tubes. The bottom four rows are separate from the upper radiator and form the lower radiator for the fuel cooler. [ I believe the new, updated radiator mentioned in the Tech. bulletin does not have this separate section]

Two connections at the top of the radiator provide for the attachment of the top hose from the outlet housing and bleed pipe to the expansion tank. Three connections at the bottom of the radiator allow for the attachment of the bottom hose to the thermostat housing and the return hose from the oil cooler and feed hose to the fuel cooler.

The bottom four rows of the lower radiator are dedicated to the fuel cooler. The upper of the two connections at the bottom of the radiator receives the coolant from the oil cooler. This is fed through the four rows of the lower radiator in a dual pass and emerges at the lower connection. The dual pass lowers the coolant temp. by 24 degree C before being passed to the fuel cooler.

That is the original radiator, the modified one supplies coolant to the fuel cooler from the bottom spigot , thru a restriction, and I believe the separate bottom four row fuel cooler section has been done away with, because with the top spigot blanked, there would be no coolant flow to the fuel cooler. Exactly what happens if you drill out that blanking, I'm not sure. Bob
Thanks for doing the research on this Bob, it's made for a good thread.

I remember asking about the lower section being separate when I had my original radiator cleaned/roded.
I had blown into a spigot and found air only came out the other spigot.
I was told all was normal.

When I got the new one as said I drilled the lower outlets.
I can't remember if they where a separate section or into the main side tank.
I'll be doing a cooling system flush next month with a thermostat change.
I'll have to try to remember to check.

[bob10]

The issue is, I think, does the modified radiator have the bottom closed off section for the fuel cooler, or not. I would say no, because the blanked off top spigot suggests that. And the restriction in the bottom spigot , plus restrictor in the fuel cooler inlet, suggests pressure/ flow regulation to the fuel cooler. What would be interesting would be to find out what setup after market radiators have [ Serk, etc] At this point I would not drill out the bottom spigots, no matter what local mechanics say. Bob
https://www.aulro.com/afvb/images/imported/2014/01/24.jpgL8711bu.pdf (http://www.aulro.com/afvb/attachments/discovery-2/65663d1379320504-new-radiator-td5-please-explain-l8711bu.pdf) (770.4 KB, 27 view . This should be taken as gospel.

[roverv8]

more info in this thread
cheers


http://www.aulro.com/afvb/discovery-2/158038-radiator-td5.html

[OffTrack]

The issue is, I think, does the modified radiator have the bottom closed off section for the fuel cooler, or not. I would say no, because the blanked off top spigot suggests that. And the restriction in the bottom spigot , plus restrictor in the fuel cooler inlet, suggests pressure/ flow regulation to the fuel cooler. What would be interesting would be to find out what setup after market radiators have [ Serk, etc] At this point I would not drill out the bottom spigots, no matter what local mechanics say. Bob


I think you have got it pretty much nailed.

The only way the cooling system can work is if the division on the bottom part has been removed.

LR must have decided that there was sufficient coolant circulation through the oil cooler without the flow through the oil cooler, so the pipe and hoses between the oil cooler and the radiator (shaded red) appear to be redundant.

http://www.aulro.com/afvb/attachment.php?attachmentid=65763&stc=1&d=1379498479

The two remaining connections (green) at the bottom of the radiator are outlets.

If you remove the restrictors the coolant flow back into the engine is likely be reduced.

It's pretty clear that drilling out the two bottom tubes will not restore operation to the old flow, and will have unpredictable results.


cheers
Paul

[feral]

If you remove the restrictors the coolant flow back into the engine is likely be reduced.

It's pretty clear that drilling out the two bottom tubes will not restore operation to the old flow, and will have unpredictable results.


cheers
Paul


Here is some anecdotal evidence to consider.

I went through my records and come up with this.

Water Pump @ 71,600ks 5/04
Radiator @ 145,000ks 3/08
Headgasket @ 157,500ks 10/08

Current ks 227,000 approx.

I recall drilling out the pipes (to match original radiator) and I did not add the fuel cooler reducer.

The biggest question mark I have is the coolant temp takes time before thermostat opens up. When at 0 - 10 degrees ambient, coolant temps will take up to 15 minutes before t/stat is fully open. Another observation is my average running temp would be in the mid 80's. Further observations is when I change my coolant I feel the temps in all pipes, therefore I am getting full circulation.

Unpredictable results?

[OffTrack]

The biggest question mark I have is the coolant temp takes time before thermostat opens up. When at 0 - 10 degrees ambient, coolant temps will take up to 15 minutes before t/stat is fully open. Another observation is my average running temp would be in the mid 80's. Further observations is when I change my coolant I feel the temps in all pipes, therefore I am getting full circulation.

Unpredictable results?

As Bob has pointed out the original radiator was in two parts so the two inlets at the bottom were a separate cooler. This restriction was removed in the new design, so the main flow travels through the full radiator.

By removing the restrictor and opening up the blocked tube you don't restore the function of the separate cooler, instead you provide two additional outlets from the main radiator which bypass the thermostat. If you have a significant amount flow bypassing the thermostat and entering engine you are going to have longer warm up times.

I have no idea how the coolant will behave on the leg to the oil cooler. Do you? Is hot coolant being dumped into the bottom of the radiator, or are you getting coolant flowing from the radiator to the cooler? And if coolant is going direct to the oil cooler from the radiator what effect is that having?

I'd take the recommendation of LR on an engineered change which is intended to improve the reliability of the radiator over backyard mechanics who think they know better.

cheers
Paul

[northiam]

The coolant off the oil cooler is the coolest coolant available after the pump. The coolant then went off to the bottom 4 rows of the EU2 radiator to be cooled even further before delivering it to the fuel cooler.

The EU3 engine having the EGR cooler required that coolant for cooling the exhaust gases and no longer available for the fuel cooler.

The new radiators bottom rows are effectively cooled further being out of the main radiator flow through heat stratification.

More like an LR engineering compromise.
Regards

[bob10]

It would interesting to compare the oil temp/coolant temp. of a new radiator fitted untouched, and one fitted with the blanks drilled. Also , even though the Tech. Bulletin says to connect the hose from the oil cooler to the top spigot [ the completely blanked off one] ,it should be possible to get rid of the secret hose & associated pipework, & blank off both ends. Is it possible to contact LR and have them clear this up? They may have an answer to what consequences come from drilling out the blanks. Bob

[feral]

By removing the restrictor and opening up the blocked tube you don't restore the function of the separate cooler, instead you provide two additional outlets from the main radiator which bypass the thermostat. If you have a significant amount flow bypassing the thermostat and entering engine you are going to have longer warm up times.

I have no idea how the coolant will behave on the leg to the oil cooler. Do you? Is hot coolant being dumped into the bottom of the radiator, or are you getting coolant flowing from the radiator to the cooler? And if coolant is going direct to the oil cooler from the radiator what effect is that having?

I'd take the recommendation of LR on an engineered change which is intended to improve the reliability of the radiator over backyard mechanics who think they know better.

cheers
Paul

Backyard mechanics....jeez, all I was doing was adding anecdotal evidence to the discussion. I'm not arguing neither here nor there. Couldn't care less. :eek:

Edit: Forget it.

[bob10]

The coolant off the oil cooler is the coolest coolant available after the pump. The coolant then went off to the bottom 4 rows of the EU2 radiator to be cooled even further before delivering it to the fuel cooler.

The EU3 engine having the EGR cooler required that coolant for cooling the exhaust gases and no longer available for the fuel cooler.

The new radiators bottom rows are effectively cooled further being out of the main radiator flow through heat stratification.

More like an LR engineering compromise.
Regards
I'm a little unsure of that explanation, perhaps you can help me out. Do you have a flow diagram of the EU3 engine coolant flow. It sounds like you are suggesting that in the new radiator, the bottom 4 row section is still there. However, that means effectively, there would be no coolant flow to the fuel cooler at all, considering that the flow is initiated from the oil cooler via the secret hose. That top spigot is now blanked off entirely. However, the bottom spigot, if you check out the technical bulletin, has a small orifice to facilitate flow to the fuel cooler. Where is that flow coming from? I suggest the new radiator is a full flow one, utilising the entire core, doing away with the bottom fuel cooler 4 row section. I haven't seen one , of course, and I'm open to any explanation, because coolant flow is such an important part of the TD5. Bob

[northiam]

I'm a little unsure of that explanation, perhaps you can help me out. Do you have a flow diagram of the EU3 engine coolant flow. It sounds like you are suggesting that in the new radiator, the bottom 4 row section is still there. However, that means effectively, there would be no coolant flow to the fuel cooler at all, considering that the flow is initiated from the oil cooler via the secret hose. That top spigot is now blanked off entirely. However, the bottom spigot, if you check out the technical bulletin, has a small orifice to facilitate flow to the fuel cooler. Where is that flow coming from? I suggest the new radiator is a full flow one, utilising the entire core, doing away with the bottom fuel cooler 4 row section. I haven't seen one , of course, and I'm open to any explanation, because coolant flow is such an important part of the TD5. Bob

Its a cross flow radiator.
The EU3 radiator is one circuit, the lower part flows through to the fuel cooler.
I have seen 2003/EU3 south african delivered D2's with factory blanked off oil coolers as the EGR cooler was deleted.

Rave shows a EU3 coolant flow circuit below the EU2.

Many have fitted the newer designed radiators to EU2 D2's, some have drilled some have not. Others have fitted the fuel cooler restrictor some have not, I have not read of any issues from anywhere regardless!

I drilled the upper blank as I didnt want to leave a dead leg in the circuit.

Regards

[bob10]

Its a cross flow radiator.
The EU3 radiator is one circuit, the lower part flows through to the fuel cooler.


I drilled the upper blank as I didnt want to leave a dead leg in the circuit.

Regards
Thanks for that, just a couple of questions. On whose advice did you drill the blank, and which way do you think the coolant flow goes, oil cooler to radiator , or vice versa? Does any one know why Land Rover said in the tech. bulletin, do not drill the blanks. How many head gasket leaks could be caused by a diversion in the coolant flow, if any? Could the change in the flow, ie opening up the blank , cause problems such as pressurising the system , and overflowing the expansion tank? Tomorrow I will go to talk to the TD5 guru at our local independent dealer, see if he has an answer. This is one subject that deserves a pedantic approach, Bob

[bob10]

Backyard mechanics....jeez, all I was doing was adding anecdotal evidence to the discussion. I'm not arguing neither here nor there. Couldn't care less. :eek:

Edit: Forget it.
It's all cool feral, we appreciate the input. Besides, Land Rovers have been making mugs like me into back yard mechanics for years, :D Bob

[Zypper]

Ok, will wade in with my 2c worth.

The First thing to note is that coolant "flow" in the various circuits (contrary to popular beliefs) is generated more by the low pressure or suction side of the coolant pump than by the high pressure or delivery side of the pump.

With the original EU2 set up (radiator with the separate (internally)section at the bottom), the flow in the fuel cooler circuit starts: when the separate small thermostat in the fuel cooler (yes there is a t/stat here!!) opens, the pump draws coolant from the oil cooler outlet, through the “secret hose” (Rave lists it as “Oil Cooler Return”) to the rad where it is cooled by a double pass across the rad then to the fuel cooler to do its job then down to the lower main hose then back to the pump to complete the circuit.

Reading between the lines I believe there was an issue with maintaining flow through the heater matrix (lack of heater performance), so the “fix” was to put a restrictor in the inlet side of the fuel cooler to force the majority of flow in this combined circuit via the heater matrix to keep knees and toes in the cabin happy!! It is my opinion that the restrictor in the abovementioned T/B does not require to be fitted as the restriction in this part of the circuit is provided by the orifice in the lower port of the later type rad(no need to have both ends of the hose restricted!!)

Coolant supply for the fuel cooler circuit for the new type rad is drawn from the lower restricted port of the rad (this coolant has already been cooled as it made its way down the rad and in fact may be cooler than the main body of coolant as this outlet is below the main rad outlet hence a possible slower turnover of coolant in this lowest section.

If I was to fit a new type rad to an EU2 vehicle I would either (1) remove the “secret hose” entirely and blank off the oil cooler outlet with a quality blank (not a chair leg stopper!!) or (2) if the “secret hose” is to stay then drill a small (1/16”) hole in the blanked off rad port to allow a very small amount of flow as a closed section may not get a change of coolant even when the system is flushed and this could lead to corrosion of the steel part of this now redundant section of the circuit. I wouldn’t drill this hole any larger as in effect you will be introducing heated coolant into the lower section of the rad leading to less efficient fuel cooling and a reduction in cooling effect overall particularly at high stress times as far as the cooling system is concerned.

In an EU3 vehicle the “secret hose” can be removed ONLY IF the EGR cooler has been/ will be removed, this will also require blanking at the expansion tank end of the small hose (8mm or 5/16” ID) that runs from the EGR cooler back to the exp tank.
I hope this can be of some assistance to somebody, remember the above is MY OPINION ONLY, but I’m sure if you study the coolant flow diagrams and apply the laws of physics you will come to the correct conclusion.;)

Cheers, Zypper.

[bob10]

Ok, will wade in with my 2c worth.


I hope this can be of some assistance to somebody, remember the above is MY OPINION ONLY, but I’m sure if you study the coolant flow diagrams and apply the laws of physics you will come to the correct conclusion.;)

Cheers, Zypper.

Thanks, Zypper. Slowly starting to form a picture. I feel at this point I should add what RAVE says about " Cooling system, - TD5 description & operation , cooling system coolant flow. " Any input would be appreciated.;

During warm up, the coolant pump moves fluid thru the cylinder block and it emerges from the outlet housing. From the outlet housing , the warm coolant flow is prevented from flowing thru the upper & lower radiators because both thermostats are closed . The coolant is directed into the heater circuit. Some coolant from the bypass pipe can pass thru small sensing holes in the flow valve. The warm coolant enters a tube in the thermostat housing & surrounds 90% of the thermostat sensitive area. In cold ambient temps. the engine temp. can be raised by up to 10DEG, C to compensate for the heat loss of the 10% exposure to the cold coolant return from the bottom radiator hose.

At engine speeds below 1500 RPM, the bypass valve is closed only allowing the small flow through the sensing holes. As the engine speed increases above 1500 RPM, the greater flow & pressure from pump overcomes the light spring & opens the bypass flow valve. The flow valve opens to meet the engines cooling needs at higher engine speeds & prevents excess pressure in the cooling system. [ okaaay, may be getting somewhere here] With both thermostats closed , maximum flow is directed thru the heater circuit.

The heater matrix acts as a heat exchanger reducing the coolant temp. [ if you have bypassed your heater perhaps note] as it passes thru the matrix. Coolant emerges thru the heater matrix & flows to the fuel cooler T connection [ see offtracks diagram] via the heater return hose. From the fuel cooler the coolant is directed into the coolant pump feed pipe and recirculated around the heater circuit. In this condition the cooling system is operating at maximum heater performance.

Coolant flow coolant hot

As the coolant temp. increases the main thermostat opens. This allows some coolant from the outlet housing to flow thru the top hose, & into the radiator to be cooled. The hot coolant flows from the left tank in the radiator, along the tubes to the right tank . The air flowing thru the fins between the tubes cools the coolant as it passes thru the radiator. A controlled flow of the lower temp coolant is drawn by the pump & blended with hot coolant from the bypass & the heater return pipes in the pump feed tube. The pump then passes this coolant , via the cylinder block , to the oil cooler housing, cooling the engine oil before entering the block to cool the cylinders.

When the fuel temp increases , the heat from the fuel conducts thru the fuel cooler 'T' connection and causes the fuel thermostat to open. Coolant from the cylinder block flows through the oil cooler, & via a pipe & hose enters the lower radiator. The lower temp. coolant from the oil cooler housing is subjected to an additional 2 passes thru the lower radiator to further reduce the coolant temp. From the lower radiator the coolant flows, via a hose to the fuel cooler.'

So from this I suggest,
1 do not drill out the spigots on the modified radiators
2 fit the restrictor
3 Do not think LR engineers are mugs.
4 my head hurts.
Simple really , :eek: Bob

[Zypper]

G/day Bob,

Thanks, Zypper. Slowly starting to form a picture. I feel at this point I should add what RAVE says about " Cooling system, - TD5 description & operation , cooling system coolant flow. " Any input would be appreciated.;

During warm up, the coolant pump moves fluid thru the cylinder block and it emerges from the outlet housing. From the outlet housing , the warm coolant flow is prevented from flowing thru the upper & lower radiators because both thermostats are closed . The coolant is directed into the heater circuit.(And the thermostat bypass hose) Some coolant from the bypass pipe can pass thru small sensing holes in the flow valve. The warm coolant enters a tube in the thermostat housing & surrounds 90% of the thermostat sensitive area. In cold ambient temps. the engine temp. can be raised by up to 10DEG, C to compensate for the heat loss of the 10% exposure to the cold coolant return from the bottom radiator hose.

At engine speeds below 1500 RPM, the bypass valve is closed only allowing the small flow through the sensing holes. As the engine speed increases above 1500 RPM, the greater flow & pressure from pump overcomes the light spring & opens the bypass flow valve. The flow valve opens to meet the engines cooling needs at higher engine speeds & prevents excess pressure in the cooling system. [ okaaay, may be getting somewhere here] With both thermostats closed , maximum flow is directed thru the heater circuit.

The heater matrix acts as a heat exchanger reducing the coolant temp. [ if you have bypassed your heater perhaps note](No problem as long as the coolant still flows through the fuel cooler to operate its thermostat, BUT if the hoses have both been plugged at the heater inlet and outlet on the fire wall this will create several dead circuits!!) as it passes thru the matrix. Coolant emerges thru the heater matrix & flows to the fuel cooler T connection [ see offtracks diagram] via the heater return hose. From the fuel cooler the coolant is directed into the coolant pump feed pipe and recirculated around the heater circuit. In this condition the cooling system is operating at maximum heater performance.

Coolant flow coolant hot

As the coolant temp. increases the main thermostat opens. This allows some coolant from the outlet housing to flow thru the top hose, & into the radiator to be cooled. The hot coolant flows from the left tank in the radiator, along the tubes to the right tank . The air flowing thru the fins between the tubes cools the coolant as it passes thru the radiator. A controlled flow of the lower temp coolant is drawn by the pump & blended with hot coolant from the bypass & the heater return pipes in the pump feed tube. The pump then passes this coolant , via the cylinder block , to the oil cooler housing, cooling the engine oil before entering the block to cool the cylinders.

When the fuel temp increases , the heat from the fuel conducts thru the fuel cooler 'T' connection and causes the fuel thermostat to open. Coolant from the cylinder block flows through the oil cooler, & via a pipe & hose enters the lower radiator. The lower temp. coolant from the oil cooler housing is subjected to an additional 2 passes thru the lower radiator to further reduce the coolant temp. From the lower radiator the coolant flows, via a hose to the fuel cooler.'

So from this I suggest,
1 do not drill out the spigots on the modified radiators
(Only a very small hole as suggested to prevent a dead circuit)
2 fit the restrictor
(IMHO this restrictor is not required as the restriction to flow in this circuit is provided in the small outlet port in the later type rad, but fitting it certainly wont do any harm)
3 Do not think LR engineers are mugs.
(No-one is suggesting they are, but unfortunately what gets written in workshop manuals sometimes loses something in translation)
4 my head hurts.
(Plenty of breweries around with a remedy for that!!)
Simple really , :eek: Bob

Cheers, Zypper.

[Zypper]

Just re-read your OP Bob, see below.....

Before the wife retires, & we go for a long drive, one of the things I would like to do is refurbish the cooling system. Apart from the hoses etc, with 364,000 kms on the clock, a new radiator might be in order. I have been looking, one mob has this spiel to go with their new radiator, not sure what to make of it, I thought it would have been just a simple swap. I have a 1999 [ although vin check says it is 2000] model TD5, cheers, Bob

This is a new Radiator to suit Discovery 2 TD5 5 cylinder diesel 1999-2004. The core of this radiator measures 440mm in height and 590mm in length.
When fitting a new TD5 Discovery radiator you need to fit a fuel cooler restrictor (part no. PCS000010), to restrict the flow of the water/coolant. This restrictor fits into the front end of the fuel cooler which is underneath the inlet manifold on the driver's side. The new radiator will have no holes at the bottom, they are blanked off.(To me, this suggests both ports are blind, this is either a typo or incorrect as there MUST be flow (restricted) from the lower port to supply the fuel cooler as per the diagram in the L/R TB.) The hoses go back onto these blanking plugs the same as they came off the old radiator.

Zypper.

[bob10]

Just re-read your OP Bob, see below.....

Zypper.

https://www.aulro.com/afvb/images/imported/2014/01/24.jpgL8711bu.pdf (http://www.aulro.com/afvb/attachments/discovery-2/65663d1379320504-new-radiator-td5-please-explain-l8711bu.pdf) (770.4 KB, 27 view

If you open this up, you will see it indicates there is a orifice built into the bottom spigot. That is the new coolant supply to the fuel cooler. The other spigot is blanked off completely, and the Technical Bulletin states quite plainly, I think, the appropriate action to take. BTW, all discovery 2 's from VIN2A 736340, and Defenders from VIN2A 622424 have had the restrictor fitted. To each his own, but I would not drill out the spigots, at all, Bob

RADIATOR - SPECIFICATION CHANGE - TO IMPROVE DURABILITY

The coolant passageways in the radiator have been modified and a restrictor was

introduced into the fuel cooler to improve the durability of the radiator.

The modified radiator can be fitted as a replacement on all derivatives up to the

above VIN numbers, and is fitted as standard from the above VIN numbers. The

restrictor, which is supplied with the radiator, must be fitted into the fuel cooler.

Illustrations 1 and 2 show a cut away view of the old and new specification

radiators.

NOTE: The feed and return pipes, (.C. and .D. in illustrations 1 and 2), to the lower



section of the radiator have been modified. Do not attempt to open these coolant

passageways into the radiator.

[Zypper]

Bob,
Woah there Neddy I wasn't intending to upset anyone, I am well aware of the contents of the Tech Bulletin and was merely pointing out the "speil" from the rad supplier you mentioned in your OP is at odds with the said TB as in the "speil' it reads as though BOTH spiggots are blank. A I stated there MUST be a flow from the lower spigot to the fuel cooler as indicated in the TB.
Re the restrictor, I stated that I PERSONALLY don't think the fuel cooler supply hose requires TWO restrictors in the one hose but indeed in later model D2'2 there may have been a factory fitted restrictor to the fuel cooler inlet and MAYBE the original radiators fitted to these vehicles (with only one spigot) did not have the orifice in the spigot? so maybe in the interests of making a "one item fits all radiator" the lower spigot is now fitted with the orifice?
Re drilling a small hole in the upper spigot Im just trying to avoid a dead (stagnant) section of a circuit.
Just trying to be of assistance.:(

Zypper.

[OffTrack]

Zypper

I agree with your description of the revised flow. The coolant system after installing the modded radiator is essentially the same as EU3 system - with the obvious exception of the cooled EGR. The RAVE description of the modified system should therefore be essentially the same as the EU3 coolant flow.

I suspect the only reason the dummy pipe is retained is to save the mechanic the hassle of removing the piping around to oil cooler and then blanking the oil cooler outlet. it serves no real purpose otherwise.

The blanking plug is PYB500040 if anyone is curious.

Cheers
Paul

[Zypper]

"The blanking plug is PYB500040 if anyone is curious."

Thanks for that Offtrack, I'll put it in my book of numbers for future reference.

Zypper.

[bob10]

Bob,
Woah there Neddy I wasn't intending to upset anyone, I am well aware of the contents of the Tech Bulletin and was merely pointing out the "speil" from the rad supplier you mentioned in your OP is at odds with the said TB as in the "speil' it reads as though BOTH spiggots are blank. A I stated there MUST be a flow from the lower spigot to the fuel cooler as indicated in the TB.
Re the restrictor, I stated that I PERSONALLY don't think the fuel cooler supply hose requires TWO restrictors in the one hose but indeed in later model D2'2 there may have been a factory fitted restrictor to the fuel cooler inlet and MAYBE the original radiators fitted to these vehicles (with only one spigot) did not have the orifice in the spigot? so maybe in the interests of making a "one item fits all radiator" the lower spigot is now fitted with the orifice?
Re drilling a small hole in the upper spigot Im just trying to avoid a dead (stagnant) section of a circuit.
Just trying to be of assistance.:(

Zypper.

Not upset, at all. Just a little puzzled [ common condition for me]. I know what you meant, but, as is with most questions here, as the thread went on, the answer became clearer. Offtracks posting of the Tech. Bulletin was the catalyst for understanding this question. From there , after reading thru the RAVE description of the coolant system, the fog began to lift. There is enough evidence to suggest , when fitting the new radiator, it would be prudent to remove the hoses & piping from the oil cooler to the top spigot , and blank off the oil cooler outlet. There is also enough to suggest no other change to the coolant system would be wise. It's all good, Bob :)

[Zypper]

Happy to be of assistance Bob.

Cheers, Zypper.

[worane]

I have been reading with awe all you have all been discussing.
I'm about to replace my Rad so thought I would cruise to see what is what in rads.
I have one question, and please feel free to shoot me down.
Could one not just bung a s/s bolt up a short cut off length of the redundant hose secured with a worm drive hose clamp? That would enable the rest of the "secret" hose to be removed.
That brings up another thought. What is the point in retaining the oil cooler.
Your thoughts please.
Regards, Nick.

[northiam]

Or this available from supercheap
WATER CAP 3/4" PAIR (http://www.rarespares.net.au/rarespares/ProductPage.aspx?product=WC34B)

Oil cooler still works as its in the engine block coolant flow.

Regards

[bob10]

I have been reading with awe all you have all been discussing.
I'm about to replace my Rad so thought I would cruise to see what is what in rads.
I have one question, and please feel free to shoot me down.
Could one not just bung a s/s bolt up a short cut off length of the redundant hose secured with a worm drive hose clamp? That would enable the rest of the "secret" hose to be removed.
That brings up another thought. What is the point in retaining the oil cooler.
Your thoughts please.
Regards, Nick.


What vehicle are we talking about? If you have a late model D2, you have the modified radiator. The early ones are divided into two chambers, the lower one being for the fuel cooler. The modified ones are a one chamber radiator, with a spigot with a restriction, feeding coolant to the fuel cooler.
I assume you are talking about the fuel cooler? There are three bits of advice I would give you. Buy a RAVE DVD , so you can start to understand your vehicle, NEVER listen to any one who advocates drilling the spigot on a new radiator, NEVER buy a non genuine , or at least non OEM, radiator. Bob

[eddy]

The genuine blanking plug are pretty pricey Plug - Land Rover Part PYB500040 (http://www.lrdirect.com/PYB500040-Plug/'sfi=PYB500040) so I went Silicone Hose End Caps 2 Pack Blanking Plug Bung Stainless Steel Braided Braid | eBay (http://www.ebay.com/itm/330726148994?_trksid=p2055120.m1438.l2649&var=540062496322&ssPageName=STRK%3AMEBIDX%3AIT) Removed the metal pipe that runs at the back of the block and the hose connecting to the closed off radiator spigot.Fitted the restrictor to the fuel cooler,admittedly seemed overkill as the spigot on the radiator is already restricted,connected the hose between fuel cooler and rad..Seems to work ok,no problems in the last year.
Yes you could block off the short hose with a bolt......looks better with a plug and one less hose clamp to leak.

[OffTrack]

This is apparently what the factory blanking plug looks like:

http://www.aulro.com/afvb/attachment.php?attachmentid=73056&stc=1&d=1392772230

It looks like it might have a reinforcing layer of some kind, but still it's pretty damn expensive.

One thing it might be worth factoring in is the proximity of the exhaust. The 180°C rating on the silicon sounds like it should be ok, but I wonder how well they'll hold up in the long term.

cheers
Paul

[northiam]

I fitted the rare spares 3/4 caps (female) about 2 months ago no issues so far.
I figured the cap directly on the oil cooler casing soaks up heat better than a plug (male) would in the other end of the secret hose.

Also when you remove pipe around the back of the head access to the FPR is so much better.

I might wrap it exhaust header tape. :)