They say heater core, Ford dealer replaced it 3 years ago. Its leaking from the drain. I have luke warm air from vents. I was told to turn the temp knob from cold to hot a few times, I did and it got hot, also the leak from drain stopped. But this is happening every few months. If I smell anti freeze and look under my truck , I see the leak from the drain. when I say leak, its a pretty nice one. but I do the switch thing from cool to hot a few times, when its gets good hot air, I look and the leak stops. the dealer still says heater core. I want to think maybe blend door is sticking but I don't understand why the leak.
Is it a bypass for the core?
I am stumped.