well ive been working on my malibu with the gn drivetrain...i hooked up a autometer guage that reads up to 250 and it taks out all the way..i changed the t stat to 160 changed radiotor and waterpump is new.....dnt no what else to do...car doesnt feel hot and doesnt seem like it wants to turn of .headgaskets are dam near fresh i havent really got on the car....what can it be....