Author Topic: MK2 GTi coolant temperature gauge reading too high?  (Read 2161 times)

Offline Connorabey

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Hello, I have a 1991 Mk2 golf GTI 1.8L 8V that I am working on at the moment for my sister.

She had it at a garage recently as the coolant temperature gauge wasn’t moving off cold even when the engine was warm and had been running for a considerable time. This garage replaced the radiator and managed to get the gauge to move away from cold (I’m not sure how they managed to do that)

I have recently picked up the car and noticed that it was still losing coolant. I replaced the expansion tank and the plastic coolant flange on the front of the cylinder head. As far as I am aware this has stopped the coolant leak, I have run the car up multiple times and no coolant is being lost from the expansion tank, it stays at the maximum line on the bottle.

The car will run up and idle perfectly, however it will heat up on the temperature gauge to around 3/4 which will start the fan and the coolant light will start flashing red. Inside the engine bay it doesn’t feel to me as if it is overheating and I can touch the top and bottom radiator hoses (they do both get hot, but not scalding hot). When the fan turns off it has cooled the engine a little and the gauge does drop slightly but it does stay around the 3/4 mark.

I took off the expansion bottle cap and placed a thermometer probe inside to which the coolant was reading around 55-60 °C.

Is this normal for the gauge to be sitting around 3/4 and the fan to be coming on when it gets there?  Do you think this could be running too hot or could it just be an issue with any wiring/sensors? Or could it be an issue with the gauge and the car is actually running and functioning as it should?

Any help on the issue would be greatly appreciated.
Thank you all in advance,