Coolant system fault ?

[Effect]

I have had about 3 times now an engine management light come on for a coolant system fault.

The car still runs fine but every now and then the temperature gauge drops right down then has to build its way back up again.

What does it sound like ?

Thanks
James

 

[arronmurray]

sounds like a faulty temperature sensor to me

 

[Effect]

where would one find such a thing ?

 

[Sinny71]

On a 1.9TDi its on the right side of the engine as you look at it. You need to remove the plastic top cover to get at it from what I can tell. Mine is showing an intermittent fault as well so I should get round to sorting it.