When I put the heater on the windows fog up. Mostly not super bad. I believe it has to be the heater core, which I do not want to change. It is not terribly bad and I can funtion the car as it is. Sometimes with the heat on wide open it clears itself up after a while.
My question is what do you guys, and girls, think about using that stop leak stuff for this? And what kinds are the best for the engine. I have used this stuff in the past with no engine problems from it.