Thread: 3.1 overheat

Hello,
I have been having a problem with my 1994 3.1 L overheating. About six months ago I had a small leak from the water pump (but no problems). I had my mechanic change the water pump immediately so I wouldn't have problems down the road. To be on the safe side, I also had all the belt and belt tensioner replaced. Then about a month ago I had an overheat. I immediately shut of the . and let it cool down and got it to the mechanic. He changed the thermostat and replaced a sending unit for the electric fan. I drove the car for about 400 miles with no problem and then it overheated again. I took it to the mechanic again and he thought there may be a air bubble so he "burped the radiator" and ran a scan of the and said everything was fine. Well within about 10 miles it overheated again. ...When the car is warming up it appears to get an air bubble in the block and the thermostat won't open until you burp it. After several burbs you can get thermostat to open and it won't overheat again until it cools clear down, like overnight. There is no oil in the antifreeze and no antifreeze smoke coming from the exhaust. A side note is that the heater won't blow heat until the system is burped. I removed the guts out of the thermostat and reinstalled it for troubleshooting and sure enough it runs to cool but no overheating. Anybody run into this problem

Basmatic

sounds kinda weird. first off bleeding the system everday wont help that much if there is a bigger significant problem. Replace the thermostat, bleed the system one more time, or until all air is outta system. If still over heats, check the upper and lower intakes, they are notorious for being junk. happened in my older 3.1.

Originally Posted by basmatic

Hello,
I have been having a problem with my 1994 3.1 L overheating. About six months ago I had a small leak from the water pump (but no problems). I had my mechanic change the water pump immediately so I wouldn't have problems down the road. To be on the safe side, I also had all the belt and belt tensioner replaced. Then about a month ago I had an overheat. I immediately shut of the . and let it cool down and got it to the mechanic. He changed the thermostat and replaced a sending unit for the electric fan. I drove the car for about 400 miles with no problem and then it overheated again. I took it to the mechanic again and he thought there may be a air bubble so he "burped the radiator" and ran a scan of the and said everything was fine. Well within about 10 miles it overheated again. ...When the car is warming up it appears to get an air bubble in the block and the thermostat won't open until you burp it. After several burbs you can get thermostat to open and it won't overheat again until it cools clear down, like overnight. There is no oil in the antifreeze and no antifreeze smoke coming from the exhaust. A side note is that the heater won't blow heat until the system is burped. I removed the guts out of the thermostat and reinstalled it for troubleshooting and sure enough it runs to cool but no overheating. Anybody run into this problem

Basmatic

Has the cooling system been pressure tested?