Guys, the light came on this morning but I turned the engine off and on again and it didnt appear.

I have just checked my coolant level after letting the car cool down (since 8.30am this morning) and the level was below the min limit!

I have since topped it up with water but will put more coolent concentrate in when I am home since we have colder mornings these days but what I want to know if there is a common problem that causes this?

I know several reasons why this can happen eg, head gasket, turbo seals, burst/split pipes etc...

If anyone has an idea, please let me know

The car is an 04 2.0TDI with 81k on the clock!