99 pontiac montana cooling problems

[joleneb]

well about four days ago i noticed my 99 pontiac montana only had heat while driving or reved while idle it only blows cold we changed the water pump and the thermostat and cleaned the coolant system still no luck on fixing the problem we have been out there every day bleeding the coolant system and it seems we get air out of it every day there are no leaks and the pressure is what is suppose to be oil looks great and i dont notice any significant drop in antifreeze can any body help me im lost now and dont know what to do

[dewaynep]

Have the coolant system tested for combustion byproducts. It sure sounds like you have a bad headgasket.

[worm6]

I just went throught this on my van (2000) It started with my heat not working at idle. If i rev it up to around 3000 rpm heat would work. Also i changed waterpump thinking it was not pushing water through heater core correctly. Finally the water got into oil and i had engine problems (knocking and ticking) I waited to long not knowing the signs of headgasket leaking. Get the van in now to have it looked at. Don't wait it will cause other problems.