I have seen some traffic today about fog inside the car and it being related to the head gasket?
I have fog comming out of my defrost duct in my car and I automatically assumed my heater core was leaking.

Condensation happens when hot, humid air hits the ice cold A/C plates. It Condensation is a part of life in those conditions. Are yous sure it's not just normal condensation


If the head gasket was leaking coolant, every time you let the engine near and idle it'd pool tons of water in the exhaust. Then when you step on the gas it would billow ungodly amounts of white water vapor out the exhaust & engine bay.


lastly, shoot 20psi into the A/C evaporator drain & make sure it's not blocked.

This is happening to me in a heat condution not A/C. Sometimes I have neither heat nor Air.

Check to make sure you have the air inlet selector knob on fresh, not recirculate. If the A/C clears up the windshield immediately on defrost, then it is probably normal. It would be abnormal if you are on fresh air, defrost, and A/C and you still had a foggy windshield.