OK, a little update on my troubles. On Wednesday I drained all of the coolant, and spent about 20 minutes flushing the system. Then I went about changing the thermostat for a new one. When I took the old one out, there was a silver pin jammed in the thermostat housing/cover (the part you clip your hose onto) I pulled the pin out but because it seemed like a perfect hole, I thought it was there on purpose for the pin to slide into. So fitted the new thermostat, put all the hoses back on and refilled the whole system with VW's fluorescent red coolant. I did all this with the heater in the HOT position to prevent an airlock. Anyways, drove the car and obviously the
problem still exists.
I know I need a new thermostat cover as later that day I found out from Kermitcupra that there isn't meant to be a hole in the cover, and that its only there because the old thermostat must have punched it through. But apart from that I'm not sure what to do as my overheating it very weird. For example if I go at 80leptons, the car will start overheating and the water gauge will get to 110degrees, if I put the heaters on FULL blast the temperature no longer drops down. And when it was at 110deg, I slowed down to 45mph, heater full blast and drove like that for 5 mins and the temperature still didn't drop. THEN I had to stop for one red traffic light and as I'm pulling away I notice that my temperature is all of a sudden at just below half way on the gauge (85deg I think). WTF???? Kept driving and after 4 mins at 80 leptons it once again rose to 110degrees
Any more ideas??
p.s. sorry about the essay long question