Skrilla01

My 91GT runs at the 3/4 mark and after idling was slowly moving up what should I check ?

Hilton

Your coolant temperature with an accurate IR thermometer.

If its getting warm after idling, then I'd replace the thermostat, its large o-ring, and the rubberized metal seal behind it.

If those don't fix it, water pump is suspect

SeanR

Has the internal T-stat seal ever been changed?

Has the radiator and fluids ever been flushed?

jeff spahn

Coolant Level. Percentage water/coolant. Fans operating? One or both?

AO

GT's do tend to run hot (2nd white line or slightly higher). If it's getting hot at idle, how about when you drive it? If it cools down, it could be a fan issue.

dr bob

What Andrew said. Are the fans running as it "gets hot" at idle?

Skrilla01

I just got the car and this is realy the first time I took it out since the bad whether but when I pulled in the driveway I noticed then shut it down.I will look into it more tomorrow it was just to damn cold out.
Thanks

nc_growler

Remember to disable the fan defeat if you are running with the hood up. Fans will never come on if you have it up and this switch isn't closed.

jeff spahn

Good point, forgot that one.

Skrilla01

Whats the fan defeat?

AO

There is a hood switch next to the cross bar on the passenger side. This switch will disable the fans as a safety feature. Close the hood, fans should come on as needed based on temp (cycle on and off).