Temp gauge phenomenon

[nikos]

Ok today I was doing a lot of stop-start driving in my au1 forte 4.0 with 153k on the clock, 35degC+ with aircon on full and a coupla passengers worth of weight. Temp gauge was consistently on the 'O' of NORMAL. I stopped the engine, went into a shop and come out 2 mins later. When I started up again the needle flicked straight to max 'H' and the warning light/beep came on. After 5sec of idle it fell back to 'O' again, and all was well. This happened after all stops.

Has this happened to anyone else in the heat? I was told that it is the water ceasing flow that imediately heats up in the engine when turned off, and when engine is turned on again it flows out replaced by the cool radiator water.

I'm assuming there is no real problem, just curious as it has never happened before. Also the car seemed a little gutless and tranny was a little whinier than usual, but I'm just assuming that was the heat and high load on the car.

Discuss

[bodes-sh]

i haven't heard of this problem on an au before, but on a patrol forum i am a member of people have had similar issues with patrols, turn off when hot, then turn back on shortly after and the temp gauge goes straight to hot, then back to normal.....i would think it is just caused by the hot coolant sitting there with no way to cool it down, then as you said, when it's flowing again it goes back to normal

[andrewts]

Yeah my car does it, heat soak I think it's called, it is normal.

[amisupposed2b]

yup happens right here on a constant basis.

I have no clue what it is, but I got used to it. Because I do alot of stop start driving too.

[nikos]

Sweet, thought so. Ta fellas.

[mik]

never had that problem, when its stone cold have a look and see if the water level has moved from normal position, if it has it might be time for cooling system check.

[InfernoSR]

Not an issue mate... unless it stay's at that higher temp...

[Mechan1k]

Yeah I get it on the odd occasion after stopping (after loaded up driving in the heat in traffic) ... just a case of heat soak. The water pump stops when engine is off ... and the temperature sensor in the back of head just reads the heat from the back of head which is the hottest part of the engine bay literally.

Once the car starts and coolant flows is comes back down to normal.

A Blueprint said though ... if it stays up in the H range ... you have problems.

[EvilChief]

two areas i would look at:

faulty WTS or bad earth (temp gauge is earths through resistance in sensor)