Temperature Gauge

[douglasgdmw]

Folks,

As I am a mechanical numptie looking for some advice.

The temperature gauge on my Mk1 Golf Cabriolet has stopped working and is not moving at all.

I suspect that it could be the thermostat however I have heard the fan coming on to cool down the radiator after the car has been idling for a while. Does this mean my diagnosis is wrong.

Also if the thermostat is busted, could I be doing any damage to the car running it like this? The car is going into the garage in the next couple of weeks to get the fuel filler pipe replaced (back order of parts) and would prefer to do this fix at the same time.

Cheers
DMW

[robin]

The thermostat regulates the coolant temperature, opening and closing a valve to the radiator circuit to allow the coolant to cool (airflow generated by car motion or fan).

If it was broken your engine would still heat up - either really quickly, if the valve was stuck shut or more slowly if the valve was stuck open.

The gauge is operated by a thermistor (a resistor that changes its resistance with temperature) that will be screwed into the block or head somewhere. Either it's bust or the wire that connects to it is bust or some fuse is broken. The thermistor is normally known as a temperature sensor or sender in mechanic speak ...

Cheers,
Robin

[douglasgdmw]

Robin,

Cheers for that.

Will check the fuses and if they are ok I will try and locate the temperature sensor in the Mk1 Golf and will replace that.

I suspect that it will be a cheap part to get anyway.

Cheers
George

[douglasgdmw]

Robin,

Apologies as getting a little bit confused by the "Golf Restoration Guide Haynes manual" as it is not really a proper Haynes manual so does not cover anything.

I have taken a couple of pictures of thr engine bay and was wondering if you could confirm which part the temperatue sender is:
Info from Haynes manual I have


The pics that I have taken (just in case I am wrong):
Pic 1:


Pic 2:


No according to the Haynes manual & some googling I think it is the highlighted red item from Pic 1 but I do not have a clue as to which one it would be, top one in black or bottom one in red. Do you have a clue or am I getting it completly wrong and should be pic 2?
Cheers
George

[robin]

Of course I might be wrong but my reading of the drawing is that the coolant temperature sensor plugs into what looks like the coolant elbow from underneath, and then I would say that it's the item circled in your second photograph.

Cheers,
Robin

[douglasgdmw]

Robin,

Thanks a lot. Knew it was better to ask you as I would have probably ended up replacing the wrong part

Cheers
George