1994 TBird running hot

[quote:31c1bd8f0d="da40flyer"]94 Tbird, 107000 miles, 4.6L engine. Normally will stay dead center in the temp guage but on any uphill, will begin heating up rapidly. It got hot enough today to trip the "check guages" warning light, first time for that. Turning off AC does not help. Coolant was checked recently during an oil change and showed to be still in good shape. However, idling, even today in 115 degree heat, the temp guage stays pretty stable right in the middle. Only moves while driving.[/quote:31c1bd8f0d]

When the last time you've changed the thermostat?

[quote:f8d079c77f="rasmataz"][quote:f8d079c77f="da40flyer"]94 Tbird, 107000 miles, 4.6L engine. Normally will stay dead center in the temp guage but on any uphill, will begin heating up rapidly. It got hot enough today to trip the "check guages" warning light, first time for that. Turning off AC does not help. Coolant was checked recently during an oil change and showed to be still in good shape. However, idling, even today in 115 degree heat, the temp guage stays pretty stable right in the middle. Only moves while driving.[/quote:f8d079c77f]

When the last time you've changed the thermostat?[/quote:f8d079c77f]

I bought the car 2nd hand about 9000 miles ago. I know I haven't changed it, I would be shocked if the previous owner did.

[quote:0e0c788b48="da40flyer"]94 Tbird, 107000 miles, 4.6L engine. Normally will stay dead center in the temp guage but on any uphill, will begin heating up rapidly. It got hot enough today to trip the "check guages" warning light, first time for that. Turning off AC does not help. Coolant was checked recently during an oil change and showed to be still in good shape. However, idling, even today in 115 degree heat, the temp guage stays pretty stable right in the middle. Only moves while driving.[/quote:0e0c788b48]

If you change or remove the thermostat, and no change; might be the heater core. If that still is not the fix, check the circuit that controls the a/c in the main fuse panel under the hood, this car turns the electric fan on when a/c is used, a problem in the wiring of the a/c is sometimes a cause for overheating due to the fan not kicking on when it should or at all. Pretty easy to check, open the hood, start the engine, look at the fan with the a/c off, then turn the a/c on, the fan should begin to spin. Be careful of the fan, hands clear.