Well I live in Chicago and the winters can get really cold out here. My problem is the heat. I have an aftermarket full length radiator in my car and at first I thought that might have been the problem (over cooling).So I got a piece of cardboard and placed it in front of the radiator and what I realized was that I actually had heat until the point my car got to about the middle of the temp gauge. When it reaches that point all it does is blow cold air, but anywhere in between, just after cold, and just before the middle of the temp gauge, I have heat!!!
Could it be the heater core if I get heat? Any help would be greatly appreciated.

I'm sorry I also posted this in the EG forum but i'm getting no help there.

 

sounds like either air in the cooling system or perhaps blown head gasket.

Also try the Tech and hybrid forums...

 

your coolant is full though right??