Heat soak after the engine is shut off causes the coolant to expand. I'm assuming because of heat expansion, the coolant level rises up and out of the overfill hole in the reservoir bottle, as there is no pressure to prevent this.I have already verified proper operation of the thermostat. The car does NOT overheat at all while it's running. Completely normal. I have also verified coolant circulation. As far as I can tell anyway, every aspect of the cooling system operation is normal, save for no pressure.I even looked to local parts stores for a cooling system pressure tester, but the ones they have do not work on the VWs.
...BTW your Bieber avatar is awesome.-Malone
run engine hot, with soapy water spray, cool area with spray and look for bubbles, don't cool too much with spray, get wet and let evaporate off.
Wait wait... You have no pressure when driving, then it boils out the overflow when you stop?
You got the upper rad hose like this? That small tube needs to constantly piss coolant into the expansion tank to purge air from the system.