Okay, so before the weather starting getting cold around central PA, i had replaced my leaking radiator, flushed the system, bled air from the bleed screw in the front pipe on the motor, and also the heater core hoses on the firewall. So my question is, lately it has been about 27-40 degrees in the mornings, car warms up fine, but under idle air does not blow out hot, somewhat a cool warm. when i drive it seems to heat up fine and blow fairly hot, but then if i stop for a few minutes, say five or so and the car is idling, air temp gets noticably cooler. Is this normal, or should it blow hot all the time even under idle? tried to see if i could bleed air from the system yesterday again, but only coolant came out, no air bubbles, so i am guessing that the system should be mostly air free. Car doesn't overheat either, so i'm guessing the water pump is ok.

 

Sounds like your blower motor or charging system
When your motor is under load, the voltage to the blower goes down, causing it to blow less hot air. Thats my guess

 

You got to bleed the heater core.

Turn the car on, turn the heat up to "HI" then remove the out going heater core water pipe (next to the battery), but not all the way, there is a tiny hole in the hose, let it bleed out all the air, then put it back on & enjoy the heat.