but i don't see how the heater core would cause that much of an issue. coolant gets pumped into it and air should be gone. plus it is not like air in the heater core should cause the engine itself to overheat.

 

Its lower then the rad which air gets trapped. Moody cars have a valve by the heater core where the air can escape.

 

i still don't see that being the issue. it isn't that low and i really don't see how the air would not work its way out of the heater core super quick. coolant should be pumped into it which is why there is a line right off the pump run to it.

 

It's a little bit of physics air will get pushed to the top of the core not out

 

but even if that was the case it still shouldn't cause the engine to overheat. plus i doubt it would be easy for air to get trapped in the heater core. coolant pumped in through the top and out through the top. should bleed super easy.

 

Believe me I don't get it either but I never had problems either. I know on my 4th gen when you fill it up and start it you can hear the air escaping under the dash

 

You are correct, air trapped in the heater core shouldn't cause the issues this fellow is seeing. Something is most certainly awry there.....