“If your car is overheating, turn your heat on full blast. When you turn the heat on in a car, it pulls heat from the engine into the cab, thus cooling the engine.”
“I was taught this in Drivers Ed…23 years ago. When in high school my buddy’s car would run really hot, I told him to turn the heat on. He wouldn’t. I had to convince him it was true by saying I would pay for the resulting damage if the temperature didn’t go down. It was the winter time, and that heat was so dang hot, we had to roll the windows down. But we watched his engine temperature drop.
I don’t believe it’s especially uncommon, but if no one ever told you, it would seem counterintuitive.”