I have the Coolant Temp / Coolant Quantity Warning light coming on at random, I have replaced the expansion tank containing the sensor so far.

The temp gauge rises as normal and when the car is warmed up it holds fast at 90 degrees, sometimes the light flashes as soon as it gets warmed up, sometimes it lights up within a minute or two of starting from cold and it can even just light up when the car has been warm for 30 mins or more, it really is at random.

The car is not running hot, nor is it losing any water at all from the system.

I would have thought the temp sensor is fine with the fact that it rises as normal and never fluctuates?

Its a 08 VRS Diesel

Any ideas?

Thanks in advance!

Edited 12 October, 201213 yr by jason6003

Mine came on this morning, so i checked the coolant level & all was fine.

Drove for 6 miles to the barbers, & when i came back out & started the car to leave it didnt come back on.

Will see if it happens again 2mora.

There are some threads on this that i read earlier, just drop "red engine coolant light" in the search box & it comes up with some threads that may help you.

Hope you get it sorted.

Any Ideas guys?

Just experienced this myself. The light comes on just as it starts up, then if you start it again a few minutes later or after a short journey is doesn't come on.

I've checked everything I can and it all seems fine.

I've been parking it on the drive recently instead of in the garage, but this shouldn't effect it.

Just experienced this myself. The light comes on just as it starts up, then if you start it again a few minutes later or after a short journey is doesn't come on.

I've checked everything I can and it all seems fine.

I've been parking it on the drive recently instead of in the garage, but this shouldn't effect it.

Hmmmm. Garaged the car last night with no issues this morning.

The weather's not been anywhere near the extremes I would have thought it would need to be to effect the car.....weird.

I'm still getting it total random times, the car can be cold, warmed up or in between! It it does come on quite often turning the car off then back on again will make it go away but not everytime, I still at a loss as to what's causing it

Give the prongs in the expansion tank a scrape with a screwdriver. If they get furry they give a false reading and the light can come on even though there is plenty of coolant.

I've already fitted a new expansion tank thinking it was that and still I get the same problem!

Mines done this a couple of random mornings. Kill the ignition, restart and it's happy. It was in the garage for another fault and they checked the coolant, etc. no codes thrown up either. I'll try cleaning the prongs in the header tank