I finally got my Trans-Am back on the road after sitting for 3 months. Before it sat, the normal temp was 220. Now it 250. While it was sitting I did start the engine and ran it for a few minutes once a week Also the last time I flushed the radiator was almost 10 months ago. I also checked the drip hole in the water pump to see if its failed and ran the engine with the radiator cap off and watched the coolent swirl so the pump is working.

Any suggestions?

 

have you checked if the thermostat is operating properly?
do you have the airdam in place?
have you checked your timing?
your fan is working properly?
just some things to check,good luck

 

Like sr.bond's suggestions the thermostat could be stuck.Also you could have an air pocket causing it to run hot.When you refilled the system did you have the heat open to circulate thru the heater core?If you have your timing advanced to far will cause it to over heat.Is the temp rising with her sitting or while you drive?

 

The temp rises that high only now when driving.
Air dam is in place.
Timing is good.
Fan is good, its belt drivin.
Thermostat check out to be ok.

If there is a pocket of air, how do I bleed it out?

 

I had to replace my harmonic balancer last week.When I pulled the upper shroud it looked like a mouse was living between the radiator and the condensor.And the radiator itself was so clog it was a wonder any air was moving thru it.Had to pull it anyhow so I washed it completly to clear all the fins/tubes.Just a thought since you're having the problem moving & sitting.

 

Just yesterday my heater core failed, so I had to change it, and I hope it wont fail for many years because I don't want to tear out the dash again. After I fixed it. I ran it like normal and now my temp is staying back at normal.

 

if it has 2 fans make sure they are both turning on(coolant sensors)