P38 Overheating

Hi,

Driving in to work this morning, suddenly got cold feet. Hmmm, the heaters blowing stone cold ... whassup. Glanced at the temp guage.



Into the red with the warning lamp lit!! I pulled over onto the verge, and suddenly the heater started working again and the temperature guage dropped back to normal. Wierd!

As I'd just passed a garage I turned back and popped the hood on the forecourt. Hand on the (empty) resevoir, I could feel the coolant boiling!! Left her for a few minutes, and then cracked the seal. Topped up with water and gave it another few minutes before cranking. Started and ran normally so continued to work. Bit nervous about this, so drove all the way in with the heater on MAX and the window down. Phew! Cozy!!

When I got to work I popped the hood again, and no sign of boiling, but definately a smell of coolant about the engine bay.

Any ideas? The level in the resevoir tank when I arrived at work was ok? No more signs of overheating, but I guess there's a leak somewhere!!

Cheers,
Ripface.

Hi, was there enough antifreeze in, maybe a small block of ice?? , Also with the engine running you can feel the top radiator hose, you should be able to compress it, if it is hard that can be a sign of the water system pressuriseing.

Sounds like a circulation problem (as the heater went cold and it was boiling) though it could be loads of things, the obvious is look for external leaks, all hoses etc, if possible do or get done a sniff test, this will eliminate any head gasket problems, but it could be a waterpump problem (as it wasn't flowing around the heater). How much water did it take? what engine is it?

Hi,

The top hose was not pressurised, 'twas one of the first things I checked!! So hopefully not a head issue.

It's a 4.0 v8. Plenty of antifreeze thanks. No sign of external water leaks. That would be tooooo easy!!

Water pump? Could be .... I suspect this'll be a visit to the stealer to see if they can work it out!



Cheers,
Ripface.

Run the vehicle until normal running temperature.

Switch OFF.

Feel the radiator surface to ensure that it is a near constant temperature across the whole core surface.

Cold/Cool areas are an indication of a blocked radiator.

when my 4.6 over heated turned out to be the return feed from the rad to the resevoir had a bit of dirt that was blocking it and was causing it to over heat some times it can be simple things, also check the viscous is working before you go spending loads of money at the garage.

If it's overheated, I'll bet you several pints of ale that the gasket on the side of the throttle body has given up the go. Very simple to fix with a bit of blue Hylomar sealant (take the whole throttle body off otherwise the bolts are impossible to unscrew). When this happened on my mates P38 4.0 it was caused by a dicky thermostat. Blowing cold air in heater, engine overheating, then all of a sudden starts blowing warm air and temp goes down.

I'd change thermostat as it's about £40 for complete unit, and the spring clips are a lot easier to remove than jubilee clips on older models. Just remember to disconnect the hose from radiator top to coolant reservoir when refilling otherwise you will get airlocks.

any wet patches or damp in the footwells??

Hi all

I am new! I have similar problem and desperately need help, overheating.
have changed thermostat, drained and bled system and instructed, changed water temp sensor as broken, car runs normally foa about 10 mins then whoosh into red and steam everywhere, top pipe warm but does seem quite stiff!

Any help with next steps is appreciated, based North wales