The vanagaon temp gauge is crap..... if you want a good reading of head /
engine temp, buy a aircool head temp gauge with sender.

there is only 2 reasons that the head gasket did blow

over pressure or bad seal of the gasket.

-bad sealing head side of the gasket, the use of a recommended sealant is a
must...also, if the matting (head side) is to flat ans polish, the sealant
won't stick for long.... this surface as to be rough up!!!

-Have a coolant pressure test done
http://www.benplace.com/pressure_test.htm

This will tell you about head cracks or a coolant components failure.

And change that extpansion tank cap.

All outer aftermarket head gasket i have seen are close to crap, i would
only use OEM VW head gasket.

Ben
http://www.benplace.com/vw.htm