Cooper fan problem and car *overheating*

[uk66fastback]

Hi all

Wife has a Mini COoper conv - 07 reg.

The problem we have is that on start up and initial drive away, the temp gauge settles in the middle as normal - then in ANY type of small queue of traffic - the temp rises slightly (enough to make the fan cut in) which should take the temp down again of course to normal - but while the fans whirrs away the temp guage continues to rise until it reaches the extreme left and the light comes on ...

I don't think the car is overheating - the gauge rises way too quickly and falls again to the middle when you move off again at a decent speed. All fluids are as they should be with the expansion bottle slightly under the max level. There's no steam, fluids being expelled etc.

Sometimes the fan stays on even though the temp has returned to normal. I've had to get out sometimes and pull the giant plug in the engine bay just to cut the noise ...

I'm thinking some kind of relay isn't working or temp sensor or something? Someone has suggested the thermostat as a possibility ... ?

There was an old trick looking at the forums whereas you could thump the fan relay at the back of the radiator but that isn't doing anything ...

Any ideas?

Cheers

[cknotty]

The first thing I'd do probably would be to get something to hook up to the OBD port to monitor the actual coolant temperature (the gauge lies) to confirm if the thermostat is working as it should.

If yours is an R53 (being a convertible, I believe they were still at this age), there is a way of showing the coolant temperature on the display in the speedo.

[Cerbieherts]

I agree, my wife's cooper was boiling over despite never going halfway over on the temp guage. The second speed fan wasn't operating! Get it checked....