Try to keep this short and sweet. Had to replace the radiator in the car due to overheating. Replaced the thermostat due to continued overheating after new radiator was installed. Bled the line to make sure all the air was out. Disconnected the battery to reset computer.

Had the water pump replaced last year along with the timing belt on that.

Anybody out there got any idea what's going on with this?? It seems since the crank shaft sensor went out a few years ago it's been nothing but downhill.

And just to be clear... this car was regularly maintained and used lightly over the last few years.

This is not a continuous problem. Sometimes it overheats and sometimes it doesn't. It can be a short trip, around town, and it overheats but on the highway it doesn't. Then sometimes on the highway it overheats and in town it doesn't. We are completely baffled!!! And just before it overheats the interior heat turns cold.

 

Had a similar problem with a '99 2.7, but usually happened on steep grade with A/C on (so can't attest to heater cooling problem). Found a leak in the tank filler insert that kept the system from pressurizing. This was the first time JB weld failed me, so replaced the tank. Had to bleed the system at least 5 times to get trapped air out of the system. Bled it slow while hot/pressurized til just a little pressure remains, let cool overnight, add coolant as needed, repeat. Did this with it parked on a slight incline. Good luck.

 

I don't think a pressure leak will cause the heat to go out just prior to an overheat condition. It sounds like a defective water pump that the impeller is slipping intermittently.

 

On my previous post I wasn't real clear. Had to get the cooling system to pressurize to bleed it. With that done it took several heat, bleed, cooling cycles (driving the car to heat it, theoretically moving the trapped air) to get all the air out. Any air in the system on this car seems to cause problems.