C5 HDi Cooling problem

[citroenxm]

YET ANOTHER... This car is blessed with the DEVIL!!

Hdi 2.o 8v 110bhp.

Cooling system problem. NEW Thermostat HAS been fitted. Cooling system flushed and filled.

Whats happening is one moment all is well, the Rad is warm to hot evenly all over, then suddenly the Temp Needle shoots up off the guage and the warning message "excessive engine coolant Temp"

If you get out the car and check it, the rad has gone cold, but the top hose is hot, and so the lower... When the cooling fan top speed goes off, it then is all ok again!!

Blocked Rad?? Faulty rad even??

Any ideas peoples??
Thanks

Paul


Oh, ALSO, it also has a blower fault! It stays on full speed. On these C5's the speed resister is an external unit to the blower, which I have found over by the clutch pedal.. so it ALSO needs one of those!!

[spider]

If you're sure the stat and there's no air locks present (rebleed it anyway) I'd suggest replacing the temp sensor. I think it uses the same one to control both the gauge / warning.

[citroenxm]

Hi andy,

Im aware of the sensor, but the RAD is suddenly ALL cold and the water doesn't pass through it.. The TOP hose from the stat IS nice and hot. I didn;t say the top hose was cold, Id understand if the top hose was cold aswell then the stat is closing up...

Paul

[spider]

If possible remove the stat and run without for a day, including letting it warm up at a standstill (as otherwise it should not get warm)

Although running without is a not a brilliant idea, its a reasonable way to check for other issues such as you appear to have. It sort of sounds like its got a massive airlock though as well, or the impeller is breaking up on the pump.

[Peter.N.]

Does the heater go cold as well Paul or just the rad?

Peter

[SaabC5]

Is the stat in the correct way?