my friend winter beater a 92 cavalier and the heater core was just replaced, but his windows freez on the inside, and if the car is siting still and u rev it, the temp goes up and it gets warm, but then as soon as u drive for like 5 minutes above 40km/h it gets cool again.
is the from the heater core???

 

dont know

this would probably get a better response in the Tech/General Engine board

 

oh my bad crap sorry people.

 

well does he have the heater on?

of coarse when you rev an engine it will tend to get warmer, however when driving you get more air flow and it will cool down..

 

sounds to me likt it has a thermostat problemor possable low in coolant. It may also have an air pocket in the cooling system and may just need to be bled out.