Light comes on when car is started from cold. Turn off the engine and back on and the light doesn't come back on.

Coolant level is fine and car runs as normal.

Any ideas ?

Is it that time already?

 

It's the "oxidised prongs false positive". With a cold engine, remove the cap of the expansion bottle. You will see 2 metal prongs dipped into the coolant. Scrape a flat blade screwdriver down them a few times, and you should find that this stops for the next several years.

That time already ?

I tried this earlier but no joy

Edited 7 November, 201312 yr by tattoo_stew69

I just put up with it!!!!

That time already ?

As in it is a common fault that usually only appears in the winter.

Do some more scrapping and it should sort it. Try a small wire brush if you have one.

Or if the cleaning of the prongs really doesn't cure it, then consider buying a new expansion tank.  I have only had to do this (the clean) once on my car in 220k miles.