A foul odor coming from the dash vents when your air conditioner is on means there’s a problem. Let’s figure out what’s wrong and how to fix it.
You’re stuck in traffic on a hot day and the air pouring from the dashboard vents stinks. Not good. Sitting inside a car that smells bad is no better than sitting in a hot, sticky car. Unfortunately, nasty odors from the air conditioner (AC) system are a common problem.
Many things can cause air from the vents to have an unpleasant (and unhealthy) odor. Here are the most common causes.
How Car AC Works
A vehicles air conditioning system cools the air inside your vehicle through a simple four-phase cycle. Refrigerant flows through several components, changes from high to low pressure, and from a liquid to a gas. As a low-pressure gas, refrigerant absorbs and expels heat and moisture from the passenger compartment, cooling the air. The moisture it removes is the water you generally see dripping under your car when the AC is running and operating normally.
Types of Car AC Smells
Stuffy, stale air
Sort of like an old gym bag, this smell results from dust and bacteria build-up in the AC ductwork caused by a dirty cabin filter. This is the leading cause of bad AC smells. Replacing the cabin air filter is a quick, inexpensive fix that is a service AutoCool provides, just call us now on 0800 772 3070 and book us in for your vehicles anti-bac blast and pollen filter change. We come to you, home or workplace, no problem.
Musty, moldy or mildewy
These smells are usually due to dirt, dust and debris buildup in the under bonnet air intake vent, trapping water and moisture on the AC evaporator and in the evaporator case. All kinds of nasty gunk (germs, mold, mildew) can fester and grow in that wet, trapped debris.
AutoCool uses commercial-grade bacteriostats and microbials to kill and eliminate spores and other contaminants that cause foul smells from an AC system.
Just call AutoCool now on 0800 772 3070 and book us in for your vehicles anti-bac blast and pollen filter change. We come to you, home or workplace, no problem.
If you do not see clear water dripping from under the middle of your car when the AC is running, it means the AC evaporator case drain hole is clogged with leaves, pine needles, debris or sludge.
Just call AutoCool now on 0800 772 3070 and book us in for your vehicles anti-bac blast and pollen filter change. We come to you, home or workplace, no problem.
A clogged AC drain can also cause water to leak into the passenger compartment, soaking the carpets and producing the perfect environment for mold to grow and thrive.
Chemical odor
A chemical odor, frequently accompanied by a moldy smell, usually indicates the AC evaporator itself is leaking refrigerant. If you can hear the blower fan running but there is barely any air coming from the vents, oil from the leaky refrigerant has trapped dust and dirt on the evaporator fins, restricting air flow from the vents.
Sweet pungent odor
A maple syrupy smell, and perhaps a slimy film on the windows, indicates a leaking heater core is seeping engine coolant into the AC ducts. Installing a new heater core can be difficult and should be left to the pros.
Just call AutoCool now on 0800 772 3070 and book us in for your vehicles anti-bac blast and pollen filter change. We come to you, home or workplace, no problem.
The Last Word
Never use caustic drain cleaners to flush your AC case. You’ll ruin expensive and difficult-to-replace AC components. Avoid running your AC only in “recirculate” mode. Recirculate mode prevents fresh outside air from entering the AC ducts. Fresh air can help dry out excess moisture.
As part of your basic maintenance plan, with the engine off and key “on,” run the AC blower fan for a minute or two to help dry out any moisture remaining in the AC case. Also, check with your dealer’s service department. Some manufacturers offer an “after-run” kit that allows the AC blower motor to run a minute or two after turning off the car.