do this test: release pressure from the bowl by opening the cap. (motor should be let cool down a lot, maybe even overnight) put the cap back on, and start the motor. let it run for about 1-2 minutes, and shut off. now open the cap and see if it built up pressure. if there is pressure, then you have a leak into the coolant system.but i'm thinking that you might just have a problem with the expansion cap. they're supposed to 'breathe' a little bit to reduce pressure. if yours isn't, then that could explain all that pressure inside.
If there is no oil in the coolant you can rule out the oil cooler so I would say it's the headgasket. If you've caught it early enough it shouldn't have had a chance to do any damage to the seating surfaces on the head or block but the only way to find out is pull the head and inspect.
before you start thinking the worst, maybe you just need to have the head bolts re-torqued???
Quote from: "VW_Commuter"If there is no oil in the coolant you can rule out the oil cooler so I would say it's the headgasket. If you've caught it early enough it shouldn't have had a chance to do any damage to the seating surfaces on the head or block but the only way to find out is pull the head and inspect. The head gasket was changed like 5000km ago ... fu@*
Quote from: "JetPo"Quote from: "VW_Commuter"If there is no oil in the coolant you can rule out the oil cooler so I would say it's the headgasket. If you've caught it early enough it shouldn't have had a chance to do any damage to the seating surfaces on the head or block but the only way to find out is pull the head and inspect. The head gasket was changed like 5000km ago ... fu@* Fixed that for ya