heater core.

bypass heater core by finding the two hoses going into the firewall and connecting them together, this will disable the heat , but no more steaming up the windshield , and by the way this will last as long as you need it too.

I let someone drive my car when the windows were fogging up from the heater core and it cracked the heads the same day. I was told that I should have cut the hose to keep it from damaging the heads