Troubleshooting Summer Overheating

[BusinessConnected]

Hello Everyone,

I'm looking at ideas/advise to get past issues with Summer Overheating in my Main P38. Basic story is that it operates perfect fine when on the move, driving around etc (Even up to 40 Degrees etc) however if I'm stuck in traffic in warm weather (30 degrees+) it will always begin to overheat.

Turning off the AC will give the car some relief, but it will still remain in a "Bit hotter than I would like" state.

I have replaced the Viscous Coupling & Fan, Thermostat, New Radiator & Have 2 x Working Air Con Condensor fans that I can see spinning when the Air Con Clutch engages etc....

The other consequence of this is that when the car overheats, subsequent starting/restarting is very very difficult... Seems to be a victim of "Heat Soak" etc etc...

I'm getting so frustrated about this thing that I'm close to heading down to my Local Jeep Dealer and getting a 2012 Plated Grand Cherokee!!!....

Any ideas would be greatly appreciated.

Regards
Heath

[PeterH]

Sounds very frustrating to say the least!
With all the things you have replaced, it sounds like the only other thing would be the water pump.
Have you hooked up a faultmate or code reader? May be a faulty temp sensor sending wrong messages.
Is it losing any coolant?
Belt not slipping?

[BusinessConnected]

Additions:
- Water Pump replaced in last 6 months...
- Fuse Box Replaced in last 12-18 months
- Just replaced Oil Sump Gasket & Front Engine Cover/Oil Pump.

I've hooked it up to the Nanocom and no errors seem to be getting toggled at all. Doesn't seem to be losing any coolant... can't hear/see any belt slippage....

[PeterAllen]

Check that you do not have a blockage in the refill tank pipe. The small hose that goes from the radiator to the refill tank can get blocked particularly where it connects inside the refill tank. Simple to check by disconnecting at radiator and blowing through. I had similar problem and found a build up in that small pipe was the culprit. Hope you get it sorted

[bee utey]

Fan shrouds are sometimes counterproductive. I have trimmed 25mm of length off a shroud on a Ford F350 so the fan tips were more exposed. This improved the vehicles hot weather performance out of sight. Ideally fans should only be shrouded up to the front edge of the blades, as air is radially thrown off the blade tips given a chance. I have modified a number of different fan setups this way with good success.

I will be getting a P38 in tomorrow for work so can have a closer look at the fan then.

Also worth considering is a twin electric fan set off a later Falcon, they have been grafted to D1/RRC radiators so I believe.

[jsp]

I spent haps of time and effort on mine, and never really managed to get it to a heat tollerant level I was happy with.

I have two radiators, and when it was my daily drive they got swapped every 50K and rodded.

Water pumps, fans, ac fans , had it all done at a few different radiator/cooling shops, had electrics tested (did have dreaded resistive cables in hot enviroment issue at first), the only thing I never did was cut vents in the bonnet or sides to let more heat out like the later models.

Only ever happned when standing still in traffic for more than a few minutes, and always took at least 5 full minutes of rapid driving to get it back down to normal temp.

I don't know if the people fitting the bigger alloy radiators are having better luck?

After LPG was fitted by an excellent fitter, it did seem to run a noticeable bit longer before the temp guage would creep up.

[BusinessConnected]

I'm contemplating getting a couple of Davies Craig Hi Flow Fans to replace the Air Conditioning Condensor Fans... and then having a Controller to run them when required.

P.S: I checked that Little Top Hose from Radiator and it seems clear.

[Grumbles]

Hello Everyone,

The other consequence of this is that when the car overheats, subsequent starting/restarting is very very difficult... Seems to be a victim of "Heat Soak" etc etc...

I'm getting so frustrated about this thing that I'm close to heading down to my Local Jeep Dealer and getting a 2012 Plated Grand Cherokee!!!....

Heath

These Rover V8's cope well with our heat stock standard if nothing is wrong with them and don't need extra fans or shroud alterations or anything else for normal use.

I'm wondering if the "difficult to restart when hot" issue is the result of coolant leaking past a head gasket and wetting a plug. When my 3.9 had a slight coolant leak on one bank I experienced hot restarting and overheating when stationary issues.

As for the 2012 GC......would be pretty hard to resist and at a great price I would expect. I did the same thing but ended up with a JKU Wrangler. Not many dollars[comparitively speaking] for a lot of car.

[BusinessConnected]

Just did a Nanocom Scan and I have a P0183 Fuel Temperature Sensor A Circuit High/Out of Range. From my research this will explain the hard starting issues...

[benji]

Had to same problem on my 93 with a dodgy fuel temp sender. Are you running the correct mix of coolant?

The reason I ask is I replaced my coolant last Thursday, after draining it out of the bottom hose, I poured 5 lt of concentrated coolant in and it decided it was full. After getting the air locks out it was still full (bugger that I thought, as I've only replaced half the coolant). Taking it for a drive (it was only 32 that day) the temp quickly rose to 98, then idling for two minutes it went up to 102 before I switch it off. At home, I drained 2.5 lt out and put 2.5 lt of water in and instantly over the same drive it went up to 93-94 and stayed there. On Sat we did 400k is 40c heat and it didn't get over 96c.

[Keithy P38]

I live in north QLD and regularly go 4wding, never had a problem with my temps, even when idling in the very hot bush land. The revs creep up a bit when she's warm but the temp never gets past half.

I run red coolant, wonder if coolant type has anything to do with it?

I've also bypassed my heater core - no need for heating up north!

[BusinessConnected]

I'm running Red Coolant also.
I need my Heater Core... gets down to below 0 up in the Mountains in Winter :)

[seano87]

What concentration are you running the coolant in?

[BusinessConnected]

To be honest I'm not certain... Coolant was done by my Mechanic after we replaced the Radiator/VC/Fan last week when we had the explosion. They are not incomptetent so I assume its as described.

[Keithy P38]

Maybe drop a half a bucket outta the radiator and double check the strength, if its a light red cordial I'd be buying some concentrate and giving it an extra shot!

As I said, mine will idle in the bush on a 45 degree day and still come back for more! No mods to my cooling system other than the heater core bypass...

[bee utey]

Pure water has a higher heat carrying capacity (specific heat) than any coolant mix. If you are running anti freeze the engine will run hotter. Reducing the amount of inhibitor solution will help cooling more than increasing the amount. I strongly suggest you contact your mechanic before changing the mix, it's not worth the risk of damage if you get the wrong concentration.

[seano87]

Pure water has a higher heat carrying capacity (specific heat) than any coolant mix. If you are running anti freeze the engine will run hotter. Reducing the amount of inhibitor solution will help cooling more than increasing the amount. I strongly suggest you contact your mechanic before changing the mix, it's not worth the risk of damage if you get the wrong concentration.

And that's why I asked the question! Along the lines of making sure its not too highly concentrated. Once upon a time I thought stronger the better. One week of it getting up the gauge frequently and it got changed again, at the correct dilution and bingo, perfect again.

[poleonpom]

Hi Heath - happy new year mate.

Have you thought about getting a cooling system pressure flush and clean out? I've heard that some blocks retain some casting sand and it plays havoc with the cooling system. You can get it done for about $120 from a proper radiator place.

Cheers,

Jonathan:)

[BusinessConnected]

It's been flush and cleaned a couple of times now...
Car operates great, even in 40 Degree Days as long as I'm moving.

As soon as I'm stationary or slow (less than 50kmh) and the AC is on I'm in all sorts of trouble.

I'll ask an "understanding" sort of question now... Does the AC Fluid Level have any impact on how "Hard" the system has to work... or does it simply result in a higher temperature inside the cabin.

I'm just not 110% certain the AC guys got the system filled correctly last time when I changed the Receiver Drier and Expansion Valve because it was cold, and they couldn't get the AC to Switch on the perform a System Charge...

Regards
Heath

[Keithy P38]

Do your revs drop much or does the engine feel like its working hard at idle with the air con on?

[Hoges]

I use the AC Delco concentrate (as used in the LS1 V8) @ 50% with demineralised water. Covers all forseeable temp ranges incl. visiting Canebrra in mid winter or Bris/Cairns in sumer. Nary a problem. That being said I'm wondering how you're measuring the temp... do you have an independent means of measurement apart from the dashboard gauge... e.g. a digital multimeter with thermocouple attachment ($50 the lot at Jaycar). Very handy for calibrating pesky temp sensors. Check the temp sensor.

[BusinessConnected]

The Revs don't drop "much" but I can certainly tell the difference between Air Con Running and Air Con Not....

[Keithy P38]

That's about normal then I guess! Not sure about the tech side of things but mine will idle at around 700rpm then jumps up to 900rpm when the ac kicks in - is there some sort of electric compensator that adjusts the revs with ac on that may not be doing its job in your case?

Just throwing random ideas out there!

[BusinessConnected]

Further diagnosis in Hot Weather today has yielded the following results

Air Con Off in 37 Degree Ambient Temp (Idling as if Stuck in Traffic)
Engine stays at middle of Temp Guage as normal (30 Minutes Duration)

Air Con On in 37 Degree Ambient Temp (Idling as if Stuck in Traffic)
Engine Temp rises to first bar to the right of middle within 2.5 minutes
Engine Temp rises to 2nd bar to the right of middle within 5 minutes (End of White/Start of Red Area)

Turning off the A/C results in the temperatures dropping until back to normal operating temp within 2-3 minutes.

All of this was performed this afternoon in 37 Degree Ambient Temps at Stationary Idle. The Front Condensor Fans weren't operating during the "Air Con Off" Test as expected. When the Air Con was switched on these came on within 10-15 seconds and were fairly loud (as such expecting that they are blowing some air).

So.. What should I do next?
Better Condensor Fans?
Check A/C R134A Level?

[Hoges]

A couple of thoughts, given that you appear to have seen to all the major components:

1. When the A/C clutch takes up and there's additional loading on the serpentine belt, is there any visible effect on the operation of VC fan?

2. I'd also check the integrity of the Engine Coolant Temp sensor and its connector (no dirt/grease etc) on top of the inlet manifold...it appears than even a small change in temp is being translated into a "large" change on the temp gauge. That's why I was wondering if you had an independent means of checking the actual temp increase rather than relying on the gauge.

cheers

[BusinessConnected]

VC Fan seems to operate the same whether the AC is on or off....
I've purchased a Laser Thermometer so I can ensure that the Radiator has an even temperature and also check temps of other areas in the Cooling system potentially.

I can feel the AC is struggling because as the overall system "warms up" the effiecency and temp of air at the vents is increasing as well with AC turned on....

[wanglemoose]

when you switch the ac on, the condenser/evaporator (one in front of the rad, I always get the names mixed up) heats up to create a heat transfer for the aircon system to work. at idle with decreased water flow and air flow through the rad it heats up more as the efficency of the cooling system is reduced by the extra heat produced by the ac condenser. you need to check the temperature drop over the radiator, if its anything less than 20 deg then you need to beef up your cooling system, a solid state fan rather than vc one and a larger radiator will always help. if you go down the aftermarket route for another rad to be built avoid at all costs a close mesh core they do not let enough air through to cool properly. good luck

[BusinessConnected]

Surely requirements for aftermarket systems shouldn't be required. I don't see anyone else experiencing issues such as this so surely something within my System is the fault.

I will await what my Thermometer tells me before moving forward.

[Hoges]

FWIW... I'm presuming you have put a gentle hose spray over/through the aircon heat exchanger in front of the radiator to ensure it's not clogged? (same with oil cooler?) Just a thought. Looking forward to hearing what the thermometer results are!
cheers

[BusinessConnected]

Yeap... got in there with the Fine Hose Cleaner and they look pretty good now....

I've ordered a New VC from Davies Craig (as they are on special) and will see if that helps also.

(This one was an emergency spare and might be old/weak as I don't have anything to compare it to at the moment).

[BusinessConnected]

Ok....
Have purchased
Liquid Intelligence 239 Radiator Flush Kit
Davies Craig Viscous Coupling
Redline Water Water
New Lucas Red Coolant
New Distilled Water 10L

I have also purchased a New Radiator but I'm hoping the above solve the issues for this car, as the New Radiator is supposed to be for the "Newer" P38 I'm getting ready.

I'll let you know how I go...

[p38oncoils]

Ok....
Have purchased
Liquid Intelligence 239 Radiator Flush Kit
Davies Craig Viscous Coupling
Redline Water Water
New Lucas Red Coolant
New Distilled Water 10L

I have also purchased a New Radiator but I'm hoping the above solve the issues for this car, as the New Radiator is supposed to be for the "Newer" P38 I'm getting ready.

I'll let you know how I go...

I had the same problem about a year a go - fitted a new radiator and a new thermostat for good measure - problem solved. I use the old thermostat as a spare, radiator went into the bin. As the cooling system hoses were old I also replaced all of them as a safety measure.

[Keithy P38]

Good luck mate! You should be able to run the standard cooling system all day every day without drama. Good to see your sticking with the factory setup.

[Hoges]

I had the same problem about a year a go - fitted a new radiator and a new thermostat for good measure - problem solved. I use the old thermostat as a spare, radiator went into the bin. As the cooling system hoses were old I also replaced all of them as a safety measure.

Sm:angel:all hijack...
Did you source the radiator locally (recommendation?) or was it an o/seas buy?
cheers

[p38oncoils]

Sm:angel:all hijack...
Did you source the radiator locally (recommendation?) or was it an o/seas buy?
cheers

I got the radiator from Hi Tech Radiators in Boniface Street, Archerfield. :BigThumb:

From memory it cost around $370.00.

[BusinessConnected]

$270 Shipped to Melbourne from Ebay. Not sure if its any good as yet... But seller offers 12 month Warranty and I have paid via Paypal so can claim back if there are issues....

NEW RADIATOR LAND ROVER RANGE ROVER P38A INLET L/SIDE 4/4.6 LTR AT/MT | eBay (http://www.ebay.com.au/itm/NEW-RADIATOR-LAND-ROVER-RANGE-ROVER-P38A-INLET-L-SIDE-4-4-6-LTR-AT-MT?item=221153880307&cmd=ViewItem&_trksid=p5197.m7&_trkparms=algo%3DLVI%26itu%3DUCI%26otn%3D3%26po%3D LVI%26ps%3D63%26clkid%3D4775346557338972142)

[wayneg]

Hoges, probably dont need to tell but just in case, the Thor rad has the top hose on the drivers side unlike the link posted.

[BusinessConnected]

Well...
I purchased some Liquid Intelligence 239 Radiator Flush, it's in the Car now... gotta drive around for next couple of days for it to do it's thing.

However I've done some more troubleshooting and notice tonight at around 15 Degrees Ambient if I sit in the Car and put the HEVAC on HI it won't deliver hot air inside the car unless I rev the engine somewhat (to say around 1200rpm....) Once I have done that the Heat is very, very hot... for a while....

My thinking is either
a) I have Air in the Heater Core which isn't escaping or hopefully
b) I have low Coolant Flow around the system which might be dodgy Radiator and/or Water Pump...

Peoples thoughts?

[p38oncoils]

Well...
I purchased some Liquid Intelligence 239 Radiator Flush, it's in the Car now... gotta drive around for next couple of days for it to do it's thing.

However I've done some more troubleshooting and notice tonight at around 15 Degrees Ambient if I sit in the Car and put the HEVAC on HI it won't deliver hot air inside the car unless I rev the engine somewhat (to say around 1200rpm....) Once I have done that the Heat is very, very hot... for a while....

My thinking is either
a) I have Air in the Heater Core which isn't escaping or hopefully
b) I have low Coolant Flow around the system which might be dodgy Radiator and/or Water Pump...

Peoples thoughts?

It's more likely that the partition inside the heater matrix between the inlet and outlet pipes is broken and allowing the coolant to circulate between the outlet and inlet without going through the heater fins. When you rev the engine the quantity of coolant going through the heater increases and some of it goes through the heater fins and thus heats the air up. I think it might be time for a new heater matrix. :(

[BusinessConnected]

Alright:
So I've run the Liquid Intelligence through the system... Radiator Inlet and Outlet look very, very clean and a fair few bits of "Gunk" Fell out from the Bottom Radiator Outlet when I was flushing it out.

However rather than fixing the problem it now seems worse!!!

Car will overheat at pretty much any outside temperature... I'm just at a complete loss to workout whats causing the issues.

With the Radiator Cap off I can see the Coolant streaming from the Radiator so there seems to be Coolant Flow from Water Pump etc....

I'm just soo annoyed right now I'm ready to head to Ebay with both my P38's and associated parts!!!!!!!

[Hoges]

Have you done any readings with your laser thermometer as yet?
Second option: to test P38oncoils' theory, disconnect the hoses from the heater matrix on the engine side of the firewall and join them together with a short piece of piping and see if you still have the same issues...
cheers

[BusinessConnected]

Hoges:
Surely the Heater Matrix isn't required for general cooling of the Vehicle?
At this stage I'm measuring 105 Degrees across the top of the Radiator and as much as 115 Degrees at the Oil Sump...

Thus I'm fairly confident the Temperature Guage is correct and accurate....

[p38oncoils]

Alright:
So I've run the Liquid Intelligence through the system... Radiator Inlet and Outlet look very, very clean and a fair few bits of "Gunk" Fell out from the Bottom Radiator Outlet when I was flushing it out.

However rather than fixing the problem it now seems worse!!!

Car will overheat at pretty much any outside temperature... I'm just at a complete loss to workout whats causing the issues.

With the Radiator Cap off I can see the Coolant streaming from the Radiator so there seems to be Coolant Flow from Water Pump etc....

I'm just soo annoyed right now I'm ready to head to Ebay with both my P38's and associated parts!!!!!!!



Surely the Heater Matrix isn't required for general cooling of the Vehicle?

I think you're correct regarding the heater matrix not being required for the general cooling of the vehicle. My previous comment was only meant to address the reason for you not getting hot air from the heater.

Getting back to the overheating problem. When you cleaned the cooling system some of the gunk from the system may have travelled through the breather hose that leads from the top of the radiator to the coolant header tank and may have blocked one or both of the orifices that are in the header tank. To start with disconnect the breather hose from the radiator at the header tank end, then get compressed air and blow into the plastic pipe on the filler neck in order to clean out any blockage that may be in the breather orifices. Please note that there are two orifices on the breather – one in the filler neck and another one at the end of the pipe that descends vertically into the header tank. You may have to place your finger over the orifice in the filler neck in order to direct more pressure to the other one.

When you have done this run the engine without the radiator cap fitted until the engine is up to normal running temperature and make sure that the thermostat has opened – run engine at fast idle to try to expel any pockets of air out of the system. When you're confident that there is no air in the cooling system then put the pressure cap on and run the vehicle as you normally would and see what happens. Hopefully this will eliminate the worsened heating situation and in stead of it being very bad it will return to just being bad. :p

[Hoges]

Hoges:
Surely the Heater Matrix isn't required for general cooling of the Vehicle?
At this stage I'm measuring 105 Degrees across the top of the Radiator and as much as 115 Degrees at the Oil Sump...

Thus I'm fairly confident the Temperature Guage is correct and accurate....

Coolant flows through the heater matrix all the time whether the heater is on or off. Just wondering whether there was any blockage in the heater matrix which would cause problems. Good to be able to confirm the accuracy of the temp gauge.

[BusinessConnected]

So I drained the Radiator and followed the "RAVE" Coolant fill method and Fast 2000rpm Idle to try and alleviate Air Pockets etc in the system...

Unfortunately didn't do much, Car still went up to Top of White/Into Red with Warning Light. Only way I could turn the temperature down was to Disable Air Con, and Turn on Heater Full Blast... This got it down to around the "2pm" Position at the First White "Notch" above normal...

All I could see when I was doing my fast idle bleed was some Steam rising from Coolant Expansion Tank, and of course the level went down a bit each time until it seemed to stay pretty stagnant...

How long should I be doing the 2000rpm Idle for?

[BusinessConnected]

My other P38 is supposed to be getting New Radiator, Thermostat & Water Pump next week... I wonder whether I should just take them all and see if they resolve the issues with this car....

At least the Radiator and Thermostat should be a quick "check"....

[Keithy P38]

Water pump is a half-hour job to change, for the price outta the uk you could change it once a year!

[p38oncoils]

My other P38 is supposed to be getting New Radiator, Thermostat & Water Pump next week... I wonder whether I should just take them all and see if they resolve the issues with this car....

At least the Radiator and Thermostat should be a quick "check"....

The radiator and thermostat would be the most likely suspects. You've got nothing to loose by trying them.

[BusinessConnected]

I'm going to grab all 3 tomorrow.... I think I'll change Radiator and Thermostat first because its easier... then Water Pump if issue still occurs :)

[BusinessConnected]

I also grabbed a "Tee Kay Head Check" Kit today to test for Combustion Gases in the Radiator/Expansion Tank...

Everything was all clear there (which was good news).

Will update when I have changed Radiator and Thermostat.

[BusinessConnected]

Radiator and Thermostat have been changed (Ended up finishing in the moonlight.. was somewhat soothing). I've taken her for a drive and everything looks great.

Obviously ambient is only 15-18 degrees so not a massive test... but I was overheating today with 22 degrees ambient temp within 3-4 minutes of driving.

I'll know more tomorrow when I pickup some New Tyres.

[Hoges]

Looking good!!!:BigThumb:

[BusinessConnected]

250km drive this morning... no problems at all ;)

[Keithy P38]

Love your work mate!

[mtb_gary]

So, was it the radiator or the thermostat that fixed the overheating?
Gary

[BusinessConnected]

Well thats the question. I always replace them as a pair anyway (because Thermostats are soo cheap) that I don't know....

[BusinessConnected]

Guys:
Curiosity got the better of me and I decided to Crack open the Plastic Header Tanks at the Top and Bottom of the Radiator.

Top of Radiator had about 50-60% of the Vents closed with gunk. Bottom looked suprisingly ok... but I guess thats because the cleaning gunk could run up and around freely.

Would suprise me if the insides of the Vents in the Radiator were clogged in some cases as well.

So I'd probably think the Thermostat is ok... although in saying that I'm binning it anyway :)

[mtb_gary]

For around $30 it's not worth the risk (and time) to keep the thermostat.
Gary

[Remy]

I have t-hatted the engine, new water pump, radiator, thermostats and guess what above 35 engine starts to get hot. I think the heat coming from the condenser when aircon also plays a role even when the cooling system is in good order. Turning the aircon off on those really hot days solves the engine cooling issue just not the occupants :(

[BusinessConnected]

I'm actually looking forward to a 35 Degree day again now myself... just to see if I have actually solved the issues or not ;)