Hi, bit confused. My 2.0 tdi elegance heater stopped getting the car nice and warm even with it turned up full. Fan speed works but no real heat is coming out of the vents. At the same time the coolant temp gauge stopped working. I thought this would be head related but all seemed well, then today when checking the oil I noticed it was really low so topped it up and temp gauge working and heater back to being hot. Anyone have any idea how these can be connected? 

Wired, agent Scully may have the answer on X files.

And what about coolant liquid level...?

If the car has an Oil/water heat exchanger (I don't know if it has, but many diesels do) there may be a sensor it it that has confused the heating system due to low oil.    VW Group Oil/heat exchangers don't have a great  reputation in some earlier models and it might be prudent to just check your coolant to be sure that there is no oil in it.

Edited 6 March, 201511 yr by Pesmog

Hi, thanks for the answers. Checked the coolant for level and oil content and visually nothing wrong. Wondered if the heating system is warmed by the engine oil rather than water? clutching at straws here! 

 

Did around 150 miles today and checked oil level afterwards and not changed and heater work as well. It has always used alot of oil and I did forget to top it up last time hence the low oil level. The two things may not be connected but would like to know in case it happens again.