Temp gauge help?

[Sam H]

when I drive the temp gauge doesn't move but after turning off and on the gauge reads correctly. I will then set off where it sits at 90 for a while then slowly drops and goes back to 0, I had it plugged in to a diagnostics tester and a 'major coolant fault' came up along with a code number but I can't remember what the code was. Is this the thermostat or temp sensor or something else? Thanks in advance

 

[desertstorm]

It will be the coolant temperature sensor, very common fault.

http://www.ebay.co.uk/itm/GENUINE-O...arts_Vehicles_CarParts_SM&hash=item2edadbca6e

Check to see if the CTS you have is black, These are the original ones and fail a lot. You can buy the CTS for £5-£6 but they are not as good quality as the genuine part.

Karl.

 

[Sam H]

It will be the coolant temperature sensor, very common fault.

http://www.ebay.co.uk/itm/GENUINE-O...arts_Vehicles_CarParts_SM&hash=item2edadbca6e

Check to see if the CTS you have is black, These are the original ones and fail a lot. You can buy the CTS for £5-£6 but they are not as good quality as the genuine part.

Karl.

Sweet, thanks a lot

 

[Munch]

Make sure you buy genuine! Mine was doing exactly as yours was, swapped it out for a new, non oem part, was worse.
But the bullet and went to audi, £32 later (if I remember rightly) and now perfect

 

[westcoast a3]

Same ^^

 

[Alex C]

when I drive the temp gauge doesn't move but after turning off and on the gauge reads correctly. I will then set off where it sits at 90 for a while then slowly drops and goes back to 0, I had it plugged in to a diagnostics tester and a 'major coolant fault' came up along with a code number but I can't remember what the code was. Is this the thermostat or temp sensor or something else? Thanks in advance

How long is the car left between turning the car off and on and seeing the temp gauge read correctly at 90°C? If its literally seconds then I would think the CTS was dodgy but if its a few minutes, enough time for heat soak, then I would guess at the stat tbh

Stat has failed and is stuck open -> car never heats up because the coolant is always diverted to the radiator -> turn car off - temperature increases because there is now no air flow over the radiator (it heat soaks) -> turn car on and see a hot engine at 90ºC -> drive the car again with air flow over the rad and it all cools down again

 

[Sam H]

So I changed the sensor but didn't solve the problem had a look today and the thermostat was indeed stuck open just clearing up for anyone else with the same problem