Extreme change in mpg in the winter

[m1tch1987]

Originally Posted by andyv40turbo

how do you check the thermostat? like where is it an how do you do it? thanks
what is operating temp? 90 isnt it? mine hangs about 50...

Usually what happens if the thermostat is stuck open it usually varies when driving ie if you go up a hill it will increase, normal driving it drops, a properly working thermostat will mean that the temperature gauge is rock solid and doesn't move.

[andyv40turbo]

Originally Posted by m1tch1987

Usually what happens if the thermostat is stuck open it usually varies when driving ie if you go up a hill it will increase, normal driving it drops, a properly working thermostat will mean that the temperature gauge is rock solid and doesn't move.

so can you free them off or is it time for a newone?

[m1tch1987]

Originally Posted by andyv40turbo

so can you free them off or is it time for a newone?

You need to get a new one, they don't cost much, get a Volvo OEM one, I think the housing is held on with 3 bolts and a gasket. Once you find that its not working and the temperture drops etc after you replace it you can then realise you are lucky that it didn't stick closed and cook the engine.