2.0 HDI Xantia passed its MOT at last!

[CitroJim]

Yes and a stuck-open thermostat causes the engine to take a long time to reach normal running temperature and in the case of an HDi, likely never. This is not good for the health of the engine generally and not good for occupants in the winter as the heater can be rubbish.

Too-cool running can cause condensation and corrosion in the sump and on a petrol, a rich mixture long after it's needed for starting and cold running. It's like running a carb engine with the choke pulled out... On a petrol it can also cause a big build-up of 'mayo' (emulsified oil) in the breathers and cam boxes.

[Stepto1]

I thought they were designed to fail in the open position to avoid engine damage?

[citronut]

I thought they were designed to fail in the open position to avoid engine damage?

i have seen thermostats which have just given up the will to open

regards malcolm