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9 Most Common Car Smells

Car Smells: What They Mean & How to Get Rid of Them

Most of us are familiar with what’s commonly called “new car smell,” which is a byproduct of “off-gassing.” Off-gassing occurs when cabin plastics, fabrics, and adhesives release volatile organic compounds. As unappealing as that may sound, many motorists enjoy the resulting aroma so much that companies sell the recreated scent via interior auto sprays and those little tree-shaped air fresheners.

While the jury is out on whether actual new-car smell can be hazardous to one’s health, any number of telltale odors can be the harbinger of mechanical woes that, if ignored, could lead to serious trouble. 

Here’s a look at what might be afoot when your car, truck, or SUV offends your olfactory nerves.

Car Smells Like Gas

Don’t worry – it’s normal to catch a whiff of gasoline from time to time inside your car. If you’ve just filled up the tank, the smell may be coming from your hands, a fuel filler cap that’s not fully screwed on, or gas that’s dripped onto the vehicle’s exterior. However, if the odor persists, it could mean a leak somewhere, perhaps in the gas tank or from a defective fuel injector. Since dripping gasoline presents a fire hazard, refrain from smoking in and around the car and be sure to have the issue checked out by a mechanic as soon as possible.

Hot Oil Smell

This is another possible fluid leak, in this case, motor oil that’s dripping onto a hot surface. The easiest way to determine if this is an issue is to look under the vehicle to identify oil stains on the pavement or garage floor or for smoke coming from beneath the hood while the car is running. To prevent engine damage, check the car’s dipstick and top off the oil level if it’s low. 

Burning Carpet Smell

Aside from the cabin being on fire, the scent of smoldering rugs typically indicates a car’s braking system is overheating. You may often notice this smell if you ride the brakes around curvy mountain roads or slow the car while descending steep grades. The best action plan here is to pull to the side of the road when it’s safe and allow the brakes to cool. If you notice the smell during everyday driving, it could mean you’ve either left the emergency brake engaged or mechanical issues must be addressed. If it smells more like burning paper, and you own a car with a manual transmission, it could signal a worn and slipping clutch.

Exhaust Fumes 

If you notice what smells like tailpipe emissions inside your vehicle’s cabin, it likely means there’s a leak in the exhaust system. Drive with the windows open and head straight to a repair shop to have this checked out and repaired, as exhaust fumes contain carbon monoxide, which can be poisonous. 

Cabin Air Filter Clean and Dirty
Clean vs. Dirty Cabin Air Filter

Moldy or Musty Smell

A moldy or musty smell from the air vents indicates moisture is collecting in the vehicle’s cabin air filter or climate control system drain lines. You may clear the humidity, and the resulting odor, by running the fan (with the air conditioning off) at full blast. The smell could also come from carpeting soaked by rain getting into the cabin. Either way, breathing moldy air is unhealthy, so drive with the windows open until the issue is resolved.

Burning Smell From Car

Burning rubber

If you notice the smell of burning rubber, it could mean engine drive belts are slipping, or hoses are loose and are rubbing against accessory drive pulleys. It could also come from an oil or other fluid leak. You can open the hood and have a look for yourself (being careful not to touch hot surfaces), but unless you’re especially adept in this regard, take the vehicle into the shop for repairs.

Burnt toast

This unmistakable odor could signal a problem with the vehicle’s electrical system, usually a short in the wiring or smoldering insulation. Again, take the car into the shop ASAP, especially if the smell is accompanied by smoke.

Sweet smell

A sweet smell from under the hood could indicate an antifreeze leak in the cooling system. This could be as simple as a loose hose clamp or radiator cap or as serious as a leaky head gasket or defective radiator. It could also mean the car’s heater core is failing. If the check engine or engine temperature warning light comes on or you see steam from under the hood, the vehicle is overheating. You should pull to the side of the road and add coolant if the level is low or call a tow truck to prevent more serious damage.

Rotten egg smell

Rounding out the trio of aromas that might otherwise accompany a poorly made breakfast is the sulfur-like smell one usually associates with an egg that’s gone beyond its expiration date. Not only can this be a disagreeable scent, but it can also be costly, as it typically indicates a problem with the emissions system’s catalytic converter. If so, the “check engine” icon on the instrument panel will usually illuminate. Converters are costly to replace, but fortunately, emissions-related hardware is required by federal law to be covered under warranty for eight years or 80,000 miles, whichever comes first.

Photo Credit: Getty / CasarsaGuru

Cleaning Out Car Smells

Aside from any of the above mechanical sources, a stinky cabin could come from any source, including food left behind, spilled soup, drinks, ice cream, or kid or pet accidents. It might be from a rodent getting into the vehicle and leaving behind droppings or a carcass. You’ll want to closely inspect a stinky cabin to identify and eliminate possible sources for the smells and then give the interior a good cleaning and freshening.

Start by vacuuming and shampooing the carpeting with household rug-cleaning spray foam, paying extra attention to spills and ground-in food. Clean both the cabin, especially the areas under the seats where debris tends to collect, and the trunk or hatch area that tends to pick up odors from groceries, sports equipment, etc. Remove floor and cargo-area mats and wash them separately; ensure they’re fully dry before reinstalling. 

For cloth seats, vacuum off dust and dirt and give them a once-over with an upholstery-cleaning product, concentrating on any serious stains. Clean and treat vinyl upholstery and trim items with a spray-on product designed for plastic and rubber surfaces. If your car has leather seats and trim, apply a leather-restoring cream using a soft, clean towel. 

If you or any passengers are smokers, be sure to empty out ashtrays regularly, air out the cabin frequently, and use an in-vehicle deodorizer to get the lingering smell out. Clean interior panels with a 50/50 mixture of water and vinegar to rid the cabin of any lingering tar from smoking cigarettes.

Finally, be sure to change or have a mechanic swap out the old cabin air filter – if your vehicle is so equipped – with a new one to eliminate any possible odors and to breathe easier while on the road, especially if you suffer from seasonal allergies.

Next Steps

If you have questions about this story, please contact us at Editors@carfax.com