Has anybody had to replace their heater core in one of these AP bodies? I have had window fogging problems in the cold mornings and the only way I can clear it is to use windex and clean this film crap off. I have seen bad heater cores in the past in cars but I am having a tough time finding a leak. My sniffer with sinus problems isn't what it used to be but today whilst on some meds and nose clear I think I could smell a slight amount of hot coolant. What metal did the factory use for cores? The radiator was copper/brass now aluminum. It had alot of corrosion inside even though I flushed every 2 years.