my heater provides heat, but once my car warms up, i can smell the scent of rubber burning and steam/smoke comes out of the a/c vent. this happens whether i’m using the regular heater or the defroster. my air conditioning works fine. i’ve had my car looked at and was told they couldn’t find a problem and that all my belts looked fine. i’m a female who lives alone in a state away from family and friends who know about cars. i don’t want to show up at just any shop for the guys to take advantage of my being a female who has limited knowledge about car mechanics. please help me.



Check the level of coolant in the radiator (when it’s cold). I suspect a heater core leak. If you are losing coolant and can’t see any evidence of a leak in the engine compartment it could be the heater core.

Is there any wetness in the front carpet?

If you can’t smell anything with the AC on, the smell has to be coming from the heater core. The only difference between airflow on “heat” and “AC” is whether the air flows through the AC evaporator (to cool the air) or the heater core (to warm the air). The same fan moves the air at all times, so it can’t be the fan.


Agree; this sounds like a similar post a week or so ago. If the heater and/or defroster are on, and strange smells come up though the defroster or A/C ducts, depending on the position of the air flow, you will likely have a problem with the heater core. It starts with a smell, and soon develops into a mist on the windshield or out of the A/C ducts. Have a good shop check it out with a cooling system pressure test which will quickly determine where the leak is. Don’t try to fix this with “stop leak” or similar stuff. Even if it works, the fix may be temporary, and your heater core capacity will be reduced.