my mark 4 golf gti turbo is very poorly and it needs the doctor to get her back on the road, can anybody help, had a new thermostat on yesterday but its still got the same illness, overheating when running, its not the head gasket i have checked, its blowing out cold air instead of hot air, the syptoms goes on and on, so my baby really poorly, and im getting really upset now.:help: PLEASE HELP ME