Engine: D5: Do I have a leaking cylinder head gasket?

[skv70d5]

Hello all,

My expansion tank sometimes (a few months) drops below its minimum mark causing the car to display an out of collant error message.

I have performed a pressure test and the system seems to be holding.

I do not see any white vapour coming from the exhaust.

What I have noticed is that after filling to the max mark, it usually behaves nicely again; however, sometimes after driving I find that the expansion tank is nearly full.


I tried to perform a CO2 test after removing half a liter of collant from the expansion tank; however, the tank became full and the coolant ran into my tester contaminating the test fluid before it had a chance to reach running temperature. T

I get hot air inside the car when I want it, and the top and bottom radiator hoses are both hot once the engine is at running temperature, so I think the thermostat is working OK.


I intend to drain more coolant before trying again this weekend in the hopes that my tester will have the chance to see if these is CO2 coming out of the coolant, as well as perform a compression test.

I would also like to perform a leakdown test; however, I have been unable to find one for diesel engines.


Am I on the right track or have I missed something blatantly obvious?