Have been looseing coolant and can't figure where it is going. Usually have to add 1 quart every 6 to 8 weeks. There are no signs of leakage even after the truck has cooled down. Had pressure test done on system and was ok. Recently it started makeing a hollow thud noise from behind the heater core area and the temp gauge will move to hot and then drop back down. It only does this every now and then. Also, I can hear fluid moveing through the hoses even after the truck is turned off. It sounds like water moveing through pipes. It runs fine. The oil looks ok and it is not smokeing. The heater also works. Very strange. Could this be a stuck thermostat?
Apr 13, 2008 at 2:58 PM
