P38 DSE Overheating (yet another)

Apologies for posting yet another plea for help, but Ive read the other posts regarding overheating, and just want to be sure before committing to the next stage. Need piece of mind you see.

Vehicle is 1996 DSE 106k miles. (Jeremy Fearn upgraded intercooler and chippped.
Vehicle has been driver all over Europe, Asia, and is now in Australia (yes Im an Aus).
The Diesels were never imported into Aust, so far as I know, Im the only one who has one here.

Anyway, have been experiencing overheating issues when Im under load (towing a boat, or a loaded up camp trip up hills).

So went the whole hog and replaced:-

• thermostat - replaced (original was still ok)
• water pump - replaced (was not broken)
• viscous fan - replaced (much nosier now)
• misc hoses - replaced
• Radiator - flushed/cleaned

Still overheated.
2 weeks later, top of radiator (plastic top) split about 4 inches.
So I ordered a new radiator and replaced it, together with a new expansion tank cap.

Still overheats, seems to be getting worse.

The system has a lot of pressure and when I removed the ccap today after it was hot but recovered back to normal temp, the cooland gushed out under a lot of presssure.

I dont seem to be loosing any water.
I dont think there is an air lock as I measured the amount of coolant going in when i replaced the radiator (also drained engine block) and it almost took 11 litres.

Here are my possible next fixes, please let me know what you think.

1. AC Condensor fans dont operate when the engine is hot, would this cause the overheating problem so severely?
2. The Turbo is warn I guess as the intercooler has lots of oil inside it, but would this cause a sever overheat?
3. Is it a blown head gasket or cracked head, but I dont seem to be loosing coolant?

My best guess is that its the head gasket, but its a bit of a job and I would appreciate help or other suggestions.

Thanks in anticipation.

The water gushing out under pressure is normal. Because it is a sealed system, the minute you open the cap you are letting air into the system and it boils.
If you are towing then the fans are a big issue and the cooling system may just be struggling to recover with the turbo and the aircon running max.
Relay 13 is Condenser Fan 1 - Bridging terminals 3 and 5 will power the fan
Relay 14 is Condenser Fan 2 - Bridging terminals 3 and 5 will power the fan
Relay 18 is AC control Relay

ps I bet its not snowing where you are. You lucky sod. Lol

Mtechuk said:

If you are towing then the fans are a big issue and the cooling system may just be struggling to recover with the turbo and the aircon running max.
Relay 13 is Condenser Fan 1 - Bridging terminals 3 and 5 will power the fan
Relay 14 is Condenser Fan 2 - Bridging terminals 3 and 5 will power the fan
Relay 18 is AC control Relay

ps I bet its not snowing where you are. You lucky sod. Lol

Click to expand...

Thanks for relay tips, I might make a manual bypass.
It heats up real fast, so I dont really think its the fans, but...?
By the way, should the condensor fans come on as soon as aircon is turned on? Rave doesnt explain that. Me thinks they only come on when aircon pressure gets too high (2 speeds).

ps: wish it was snowing the other day. 4 days of constant 43+ (45.9).

Hello Rocky, you are not getting all the air out of the cooling system and this explains the excessive pressure as the water boils and you get all the voids filled with superheated steam.

Folks have many methods of getting rid of air locks, find one that works and stick to it. Mine is explained here for a different V8 variant but you should be able to adapt it to your needs.

Rover SD1 Tips 'n Tricks - #2 - V8 Coolant Fill without Airlocks

Regarding possible head gasket leak do nothing without first performing compression tests and/or leak-down tests. Google will tell you how.

Thanks Ramon.
The Tips and tricks is a good read, only problem is that there is no radiator cap on the diesel variant, the only way to fill is via expansion tank, however I will do as suggested.

I too felt that the origianl culprit was an airleak, but I carefully measured the amount of coolant into the system and it took almost 11 litres. The workshop manual states it will take 11.3, so even if Im half a litre out this shouldnt affect overheating so severely or should it?

I have all the parts now for doing a head gasket replacement, but would rather not do it if I dont have to. Given the vehicle has a tenency to blow those gaskets, would you change the gasket regardless?

cheers Karl

water pump - replaced (was not broken)>

I've seen peeps on this forum recommend that a new water pump is fitted to cure the problem. I've never ever know a water pump to cause over heating unless the bearing or water seal has failed or the engine has frozen solid and damaged the water pump when trying to start the engine.

I have seen a water pump impeller that had been worn by pumping water, but that was removed from a scania engine that had cover a millon plus miles.


viscous fan - replaced (much nosier now)

They do go wrong and fail to lock up correctly


misc hoses - replaced

I've know hoses to break up internaly and cause restrictions.
Have you replaced the all the water hoses and remember that the heater rad is part of the cooling sysytem as well.


Radiator - flushed/cleaned

You 've stated that you'e replaced this.


Have you checked that the air con rad in front of the cooling rad is totally clear allowing full air flow.

The air con fans are only there to provide air flow for the a/c rad NOT THE ENGINE COOLING SYSTEM.

Also check that there is water flow through the little pipe between the header tank and radiator to help bleed the air out of the system.

Have you done any sort of sniff test and/or pressure test??

Im going to be the person of doom here and say I had these exact symptoms on my DSE and it turned out to be a cracked head - one new head later and all was cured - not saying this is your problem but it may be worth looking at.

Also - the rad - is it genuine or aftermarket??

-Wills

kzrocky said:

Thanks Ramon.
The Tips and tricks is a good read, only problem is that there is no radiator cap on the diesel variant, the only way to fill is via expansion tank, however I will do as suggested.

I too felt that the origianl culprit was an airleak, but I carefully measured the amount of coolant into the system and it took almost 11 litres. The workshop manual states it will take 11.3, so even if Im half a litre out this shouldnt affect overheating so severely or should it?

I have all the parts now for doing a head gasket replacement, but would rather not do it if I dont have to. Given the vehicle has a tenency to blow those gaskets, would you change the gasket regardless?

cheers Karl

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Hello Karl,

First of all I had the temerity to wander into a diesel universe with tips to solve a Rover V8 problem, so I cant add much to you personal experience other than the observation regarding expelling all the air would be desirable..

I would not rely on the coolant system capacity figures, even so the equivalent of 0.5 lts or air is a lot of space in the upper reaches of the system where the problems occur.

I just dont know about gaskets on your variant.

hi i removed the air con rad on mine and it made a big difference to engine temperature,
bearing in mind i live in the u.k. where a, we only have about 2 days a year where you might consider using air con and b, no one can afford to use it with the price of fuel here!!!!!!!!!!! cheers.

does the diesel have the little pipe on the top of the rad to the coolant tank, if so ensure this is clear of all fluid and any blockage to allow air from top of rad to escape. this has been know to cause problems on the petrol engine!

A little tip, years ago I used to strip & rebuild gig industrial diesel engines, & found the best way to eliminate air-locks was to run the engine WITHOUT the rad/headed tank cap, if the engine was new or dry, it would be started & immediately filled whilst running, this way, the coolant was pumped around the engine WITH any air, & this, again with the air would get pumped out into the headed tank/rad.
If you already have coolant in, then remove the cap & stert her up & run for 1/2 hour or so, 'blipping' the throttle every now & again will speed the flow & any air will bubbles out, expect to get 'overflow' as it warms & expands, & of course, if any air IS present, the level will drop, thus more coolant required.
Also, watch the return flow into the tank (get someone to blip it as you look) there should be a steady flow as it circulates.
I still 'do' it this way on all engines, & never have problems with air-locks.

Hi all.

I have a very similar problem, 3 rads cracked in the last 2 years. I've replaced the viscous fan with a Kenlowe, replaced thermostat twice, removed head and had it checked for cracks/leaks, rebuilt engine with all new head bolts, pressure tested system with engine running under load - no excessive pressure detected. Checked water pump impeller etc. Runs like a dream most of the time, engine temperature absolutely normal then without warning will deposit steaming hot water, upon inspection this has been because the rad is cracked. Any help much appreciated as I've run out of ideas.

Hi,

Sorry i was reading the postings and although i have a similar problem i have been told 2 different reasons.

My 2.5 DSE over heats going up hill but the main fan does not kick in (make loads of noise) 1 garage has tod me it should and its the viscouse coupling at fault the other says its not. any ideas?

Many thanks

Jules

death660 said:

Hi,

Sorry i was reading the postings and although i have a similar problem i have been told 2 different reasons.

My 2.5 DSE over heats going up hill but the main fan does not kick in (make loads of noise) 1 garage has tod me it should and its the viscouse coupling at fault the other says its not. any ideas?

Many thanks

Jules

Click to expand...

Just had the Viscous Fan, Water pump ann serpentine belt replaced on 96 DSE, total cost £166.50 (parts and labour) Not had a trailer (horse) on the back yet but seems to be running cooler than it was prior. Had serious overheat last time I towed, hence replacement parts, the Fan was only free wheeling but the overheat had knackered the impeller on the water pump. Apparently these are only made of Plastic and are prone to disintegrating when hot.

My next port of call will be the head gasket/head if it over heats next time i tow. I have the same probs with no loss of coolant. Will keep you updated.

Hi,

Sorry my comp has been down.

I checked my thermostat and it was stuck shut, so that got changed. Also took out the water pump which was blocked with what looked like lime scale so ive changed the water pump too.

All is good and she is running like a dream apart from the " i hate starting when hot" problem

HI!
I have similar problem with my 96 dse. I had in new the radiator (aftermarket), water pump, thermostat,hoses,etc.....still overheats when under load (load under the accelerator jejej)...the temp needle goes up to about 1 oclock! (doesnt go in to red!)...ass soon as the road gets horizontal the temp drops down to 12 oclock again...and everything as normal!
No coolant liquid in the oil and no oil in the water system...and no strange smokes from exhaust!
Dont know what to think!
Could it bee the head gasket and not notice anything but overheating? I mean...when the head goes normally you see coolant in the oil system...oil in the coolant system..overpressure in the coolant system....fumes in the exhaust...and so on!!!
Am I right????
Hope you can help!
Adal Trujillo

Rangeroverp38DSE said:

HI!
I have similar problem with my 96 dse. I had in new the radiator (aftermarket), water pump, thermostat,hoses,etc.....still overheats when under load (load under the accelerator jejej)...the temp needle goes up to about 1 oclock! (doesnt go in to red!)...ass soon as the road gets horizontal the temp drops down to 12 oclock again...and everything as normal!
No coolant liquid in the oil and no oil in the water system...and no strange smokes from exhaust!
Dont know what to think!
Could it bee the head gasket and not notice anything but overheating? I mean...when the head goes normally you see coolant in the oil system...oil in the coolant system..overpressure in the coolant system....fumes in the exhaust...and so on!!!
Am I right????
Hope you can help!
Adal Trujillo

Click to expand...

When you say the needle goes to "1 oclock" do you mean just to the right of vertical? If so I would say that is normal. Mine goes up there up steep hills in warm weather especially with the caravan on the back
If it comes back down quickly I would not worry. Could be that the viscous fan is getting a bit tired.

Just like one other poster in this thread, I hate to be the harbinger of doom but you just have to consider the possibility of a cracked head.
Just like many others I tried loads of other 'cures' but I could have saved a fortune if I'd put the new head on earlier (like 2 rads which overpressured and split the little plastic tube on top, head gaskets, skimmed head, etc, etc. A cold pressure test after skimming the head didn't show up any cracks, but when it got hot, it slowly built up pressure, the hoses went rock hard and then the needle would suddenly swing into the red and power would go as it went into limp mode.
The bugger of it all was that I could drive around locally all day with no problems, but 20 minutes into a motorway speed run and - here we go again!!
I hope you are lucky and it is one of those other things, but it took a new head for mine to run properly again, and even worse now, although it is running great I still don't trust it fully because of all the false hopes that I'd got it beat.

Rangeroverp38DSE said:

I had in new the radiator (aftermarket)

Click to expand...

I had problems like you describe with an aftermarket rad. It was missing it's baffle which sits in the centre of the rad at the top. The function of this small plastic piece is to stop coolant coming in one side and then going straight along the top and out the other side without passing through the rad itself.

After sticking a genuine rad in from LR all my problems went away.

-Will

Some folk have all the luck - my rad from the LR dealer rad lasted 4 days!