I posted this topic on Troubleshooting last week and didn't get enough ideas. I have a problem with my coolant/tank. This happens frequently. I'll drive my car for a while. When I turn it off and open the hood I will see that the coolant inside the coolant tank is bubbling/boiling. Steam comes out of it as well. Also sometimes I can hear a high pitched whistling coming from the tank. I've replaced the serpentine belt,tensioners, fuel pump at 54k and the water pump at 56k. The car runs just fine. The temp gauge is at normal reading. It usually reads on the exact spot. Could the coolant mixture be wrong? i doubt that though. I replaced the filler cap and that didn't help. I heard from my last other post about a thermostat being stuck or a bad head gasket, but I have no idea what could be causing this. I am getting worried about it. I need to fix this problem before it gets worse. Any ideas? Help.
Zetec ATX 56k.
