Car smells: How to Get Rid of Mildew and Mold in Your Car’s AC
How to Remove Mold and Mildew Smells from your car’s AC
If your car’s air conditioning (AC) emits a musty, moldy odor every time you turn it on, you’re likely dealing with mold or mildew growing within the system. The odor can smell like a locker room, sweaty gym socks, or even a sour smell. This is not just an unpleasant experience but can also pose health risks by circulating mold spores through the cabin. Fortunately, there are effective ways to remove bad smells from your car’s AC system. This guide will explain why mold develops in your car’s AC system, how to remove it, and how to prevent it from recurring.
Why mold and mildew form on your car’s AC evaporator coil
The older R-12 AC systems didn’t have this problem. However, the R-134a systems aren’t as efficient as the older R-12 systems. To get the same cooling power, car makers had to pack more cooling fins into the small evaporator in your dash. AC evaporator coils remove humidity from the air, and the condensed water is supposed to drain off the fins. However, due to the dense pack of the fins, capillary action keeps some of that water clinging to the closely packed fins. When outside air passes across the water-soaked fins, airborne bacteria and mold spores deposit on the fins and start a science experiment. After you shut down the AC, the water develops mold and mildew, which causes the smell.
To make matters worse, the mold and mildew can develop slime that clogs the condensate drain tube. When that happens, the AC condensation can’t drain out of the evaporator box; instead, it drains onto your passenger carpet.
To make matters worse, many car owners don’t change their cabin air filters on time. A clogged cabin air filter reduces airflow, and that prevents the evaporator coil fins from drying off completely, making the problem even worse.
Avoid fixes that don’t work
If you search the net, you’ll see all kinds of suggestions for spraying Lysol into the air ducts. If you’re going to try this, make sure you inject the spray into the recirculation vent located under the dash. Even then, this treatment only lasts for a few weeks because it doesn’t kill off all the mold and mildew. There’s a better way.
Clean the evaporator coil and the entire heater box with an HVAC disinfecting foam
Kool-it makes an antibacterial spray foam that not only knocks out the science experiment growing
Shoot evaporator cleaner disinfectant directly into the heater case to kill mold and mildew and coat the coil to prevent it from re-occurring
inside your dash, but also treats the evaporator coil to prevent it from happening again soon.
The manufacturer says that one treatment lasts a full year. I have no connections with the company, but I have used their product, and it works well.
How to use Kool-IT to remove smell from your car’s AC
NOTE: The video link below is designed for a shop. So it recommends placing the spray can tube directly into the condensate drain from underneath the vehicle.
You don’t have to do it that way. You treat your vehicle without raising it. Follow the steps below.
1) Locate the condensate drain tube
The condensate drain is usually located at the bottom of the heater box on the passenger side. You may have to remove some console trim pieces to see it. It’s a black rubber tube that takes a 90° turn out of the heater box and then goes down through the floor to drain water onto the ground.
The condensate drain is connected to the heater box and going through the floor to the pavement.
Before you disconnect the drain tube from the heater box, lay down some old towels directly below the drain to capture any scum water still inside the heater box. If water comes out, that means the drain tube was plugged. Once the water stops draining, clear out the drain tube using compressed air or a pipe cleaner.
2) Connect the tube to the can of Kool-IT
Next, feed the injection tube from the can of Kool-IT into the drain opening on the heater box. Snake it up into the heater box. Then press the nozzle on the can and load the entire can into the heater box. Once the can is empty, remove the tube and reconnect the rubber condensate drain.
The product will foam up and fill all the nooks and crannies in the evaporator fins. The antibacterial cleaner will kill the mold, clean the evaporator, and remove the smell from the car AC.
The foam will turn back into a liquid and drain out the drain tube onto the ground, taking all the slime mold with it.
Run your AC at full blast to dry out the evaporator coil. The treatment lasts about a year.
© 2012 Rick Muscoplat