A4 temperature gauge

[magpies]

Hi
my temperature gauge stopped working some time ago and now sits at the cold stop unless worked hard - towing up hill for example - when it suddenly reads 90degC and stays there until not working as hard when it returns to cold.
I did have a garage check the sender and they say it is reading correctly.
Any ideas

[fitzyr]

Hi
Did you check thermostat. More than likely your problem if temp sender switch is ok.

[00161wj]

What sort of garages do you people go to? Replace the thermostat