We were just driving along in our 1.9 JTD ELX diesel and suddenly the temperature gauge swung wildly to the top and then returned to about middle (where it should be) and then crept up the scale alarmingly. The electric fan did not come on.

When we checked it the water level was Ok and there were no leaks The radiator and engine block didn't feel too hot either. I tried to run the engine at home to see if the fan would be triggered as the car was stationary but the needle never crept above middle significantly, just slightly above.

I think this is a thermostat problem - haven't checked the fuse box, which is (I guess) in the glovebox to the best of my knowledge. I don't have the handbook so I don't know which fuse is blown.

Please advise if you can.

On another unrelated note I have found the standard fit (for my 2001 Y model at least!) Pirelli P6000 tyres are very expensive for their size. I found a place called Alba Tyres that will do them at around £55 each (better than the £65-£75 I've been quoted!)

Are you sure its not simply an electrical problem, with the gauge itself misreading and everything else being fine?

If you do suspect the thermostat, its probably wouldn't do any harm to change it. As a precaution.

How many miles has the car covered? Is the water/anti-freeze mix correct? Does it need changing? Could there be some corrosion in the system? Is there an air-lock in the cooling system? Does the heater still work OK? What about the water pump (if that seizes, it'll take out the cambelt (and rest of engine) with it)? How well has the car been serviced and maintained to date? Could there simply have been something (like a plastic bag) blown onto the radiator air intake which then fell off again?

Sorry I can't help you anymore as I am just about to head off on holiday No doubt somebody else will be along to assist after you have answered the above questions. Good luck.

Hi,

I've also had intermittant probs with temp variation.
Seems like a sticking thermostat too.
The fan won't come on because the rad never gets hot enough, as all the hot water stays in the engine.
A new thermostat will cost around £50 - yes that's right, aparently it comes with a new housing too.
The temp can swing quite quicklyfrom hot to cold once it does open.

Graham