Creamy expansion tank
 

hi all, i have just bought my first volvo t5 v70 and there is a creamy mayo in the header tank, is this the heat gasket?? the dipstick is fine as is the rocker oil filler cap its just the water header gunked up, any ideas please is the head gasket going? any help would be very welcome

Best get a sniffer test done,could have had the head gasket done and was not flushed out with any luck,or some radweld type stuf used just to get sold if unlucky.

The first thing to do is change the oil cooler/heat exchanger if it is the version with the cooler on the back of the sump .
also if it is auto gearbox there is another water/oil heat exchanger in the radiator ..

just picked up the t5 and not too good.... the expansion tank was fit to burst after only a few miles, but the temp gauge stayed in the middle of the gauge so was not in the rest but exremely hot and gushing like i guizer.... Head gasket??? also the car has 215k on the clock...

If the coolant was above 100 Deg C which isn't difficult on these engines when you release the cap the loss of pressure lets the water boil, the increased pressure prevents the coolant from boiling. This could be what you experianced, I would try running the engine from cold with the coolant expansion tank cap removed and see what it does, if the head gasket is shot then you might see bubbles as soon as you start it up - Mike

ok will try that but the creamy mayo in the tank looks like it got worse after the journey home, and the oil light started to flicker too..

have decided to strip it down, its gotta be the gasket, but thanks for the feedback guys