Hey Y'all,
I have a 97 3.1 monte. 60k miles on it. I've replaced the following items. Head gaskets, Intake gaskets, t-stat (acdelco), radiator, water pump(acdelco). Backflushed cooling system, Bled air out of system. Here's my problem. I've done all this work in a heated garage. When I start the car in warm conditions. It heats up normally and stays that way. However, If I start it the next morning. (30/40 degrees out) It doesn't blow warm air out of heater and eventually the temp gauge will slowly climb to the red zone and overheat. At that time I'll bleed the air out at t-stat and re start it. It usually is ok after that. Sometimes the heater will start to blow cold and if I rev it up the guage will drop to normal and blow warm again. Does anybody have an idea why colder conditions the day after would cause this? How is air getting introduced into cooling system and stopping the flow of coolant?
Please, Please, Please help me. It only has 60k. Good car.