Condensation in the heater case may cause a musty odor from the heating, ventilation and AC (HVAC) system after sitting for two hours or more. Our technicians tell us that a cleaner is available for the heater case and the drain system should be checked for debris.Google+
Car Problem Reports
Volkswagen Jetta TDI Odor from HVAC vents
Volkswagen Jetta TDI Problem
Average Mileage: 42,720 mi (10,000 mi - 70,000 mi)
Visitor, 2010 Volkswagen Jetta TDI, 59,600 mi
Vinegar like odor from HVAC. Becomes pronounced when AC is on. Have not solved yet, will likely take to dealer for cleaning.
Visitor, 2010 Volkswagen Jetta TDI, 42,000 mi
A musty odor coming from the air conditioner vents. Dealer offered to check it for a price, we decline and bought a new AC filter from auto parts store, which I will replace myself.
Visitor, 2006 Volkswagen Jetta TDI, 70,000 mi
I have begun to notice a distinct smell of antifreeze in the car, especially when climbing mountain ranges. The smell emanates from the vents even if the fan is completely turned off. No solution yet, but I suspect a slight leak in the heater core or the attached hoses. It resulted in extremely lungs for several weeks after an 8 hour road trip.
I have noticed when I started using the AC in the Spring now, AC smells like mold. After leaving the fan on high for a few minutes, the smell disappears (and or i'm just getting used to it).