I'm new to the forum board and I did a search for this problem but didn't come up with anything. I have a 98 GT GP. Recently I noticed that the car's temp was above normal when sitting (260 deg). Never had the temp that high before even on the hottest days and it's winter now. Checked the coolant and it was low. Filled it back up and things were fine. Run the car for awhile, the level drops and the temp goes up. There is a new thermostat in. No visible leaks on the ground underneath. I'm thinking bad head gasket? Anyone have the same problem ?

Same thing happened to me when I had my GT, I had about 55 or 60K on it. I replaced the water pump and that brought the temp down and I never had a problem again...someone may have other suggestions

Wow.....Mine just hit the 60k mark. I read some other things about the water pump needed to be replaced around this time but they didn't mention high temps. Cool...that helps alot.

If the high temp is due to low of coolant, it's possible it is leaking via the upper intake manifold.

I think I remember reading something about a recall or something about leaking upper intake manifolds on the L36 in the last month or two.