Tips for what to do if your car AC or Heater Smells.
If you find out a nasty smell coming from the vents when you starting your car and cranking the A/C or heater to max, you are not alone. You may wonder is there something wrong with your car. Before you can figure out how to get rid of the odor, it’s important to tell what types of smells and what they could mean for your vehicle.

Why Your Car A/C or Heater Smells?
The source of a strange odor could come from outside or inside. The air conditioning system of your vehicle can either condition air from outside the vehicle, or condition the air that’s in the vehicle by recirculating it through the system. Strange odors can come through your A/C from inside or outside sources, and your car can usually be resolved by removing or driving away from the odor. However, if your car A/C smells like gas, vinegar, mildew, or even like it’s burning, you’d better pay attention to the smell since there may be cause for concern.
What does it smell like and what it means for your vehicle?
- GASOLINE
If your car A/C smells like gas, the smell of gasoline is usually an indication of a fuel leak.
While your cabin air filter can filter out dust and other harmful materials, it’s not strong enough to able to filter out stronger smells like gas. So, if your vehicle is leaking gas, that likely the smell of gas will get sucked into your cabin through the A/C.
It’s very important to have your fuel system checked out by a mechanic as soon as possible if you smell gas coming from your vents; since a gas leak can be very dangerous. If you smell fuel in your A/C, it’s best to turn off your car immediately. Then to have your fuel system inspected and repaired by a mechanic if necessary.
- VINEGAR
If your car A/C has a pungent smell like vinegar when you turn on your A/C or heater. The source could be a bit tricky to pinpoint. In rare cases, certain types of mold can cause an odor smell like vinegar. However, there may be other much bigger issues that cause pungent smell in your A/C. Leaking battery acid or ozone emissions may cause a strong sulfur smell that smells like vinegar. You may try to use a vent and duct cleaner to eliminate the vinegar odor issue. If that does not help, it’s better to have a professional inspect your car’s A/C system.
- MILDEW OR MOLD
As your vehicle ages, bacterias can grow in the system where moisture typically collects, especially on the A/C’s evaporator. Mold and bacteria thrive in moist and enclosed spaces, particularly your vehicle’s cooling system. A mildew-like smell can get blasted into your cabin through your A/C vents as a result. You may try a vent and duct cleaner, which allows you to spray into your vents to help neutralize the odor. Or purchase anti-bacterial products that can be applied directly to the A/C and into the vent system to kill bacteria. However, this can only work if the mold or mildew problem is mild. For a better solution, it’s better to have a professional inspect your car’s A/C system and make a deep clean if necessary.
- A BURNING SMELL
If your car’s A/C smells like burning rubber or plastic, that’s an indicator of issues with the A/C compressor, burning wires, or electrical shorts.
If your car A/C smells like burning oil, that may cause by oil leaking issues. Since oil can leak from engines through gaskets, hoses, and even the oil filter over time. It can emit a burning oil odor that can blow in with your A/C when this leaky oil hits your hot engine or other heated elements under the hood. In this case, you should see a technician as soon as possible to locate and repair the leak.
A burning smell from your car’s A/C is never a good sign in general. Each type of burning smell can be caused by a number of issues. It’s hard to diagnose the problem just by the smell, it’s better to have a professional inspect your car in this case.
- A SWEET SMELL
A strangely sweet scent is the smell of anti-freeze which is a highly toxic substance. A sweet scent in your car’s A/C could indicate an antifreeze leak in your cooling system. Leaking coolant can be detrimental to your vehicle. If you smell something sweet in your car’s A/C, it’s important to have your vehicle checked by a mechanic and repair the leak.
A/C air filters collect dust, dirt, and pollutants; therefore, the buildup of which can cause unpleasant smells from your vents when you use the AC or the heater. To eliminate stinky and weird odors, make sure you clean your car’s A/C filter every few months.
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