When the Air Freshener Isn’t Enough…
When people think of diagnosing car issues, they usually picture things like reading codes, investigating fluid leaks, and listening for loud noises. While those are all important parts of diagnosing issues, mechanics and knowledgable DIYers can diagnose an amazing array of issues from the smell alone. If you’re bringing your vehicle in to the shop and can identify one or more of these smells for the technician, it will help them discover and fix the problem even faster.
Below you’ll find a list of common car smells, and what the likely causes are.
Most smells will disappear once the cause has been dealt with, however, sometimes an annoying smell can persist even after the root cause is fixed.
There are many possible causes of a gas smell. It could be as simple as having tracked gas into your car on your shoes while filling up the tank, or a cracked gas cap. It could also be something more serious, such as a tank leak, line leak, injector leak, faulty charcoal canister, or faulty fuel pressure regulator. If you don’t think it’s a cracked gas cap or gas tracked in on your sneakers, bring your vehicle to your trusted mechanic for a professional diagnosis.
Mouldy smells are most likely due to dirty upholstery or carpets. A spilled drink or bit of food caught under the seats is the likely cause. Try a thorough clean yourself, and if that doesn’t resolve the issue, consider a professional detail. Pros have the equipment and products to get your car’s interior into like-new condition.
Musty smells are caused by mildew, which grows in damp places. Sometimes water gets trapped in the Air Conditioner evaporator and promotes mildew growth, especially if the AC isn’t used very often. Next time you drive, fire up the AC on full blast for a few kilometres to dry the system out (wear a sweater if it’s cold!). If that doesn’t fix the problem, the smell could be coming from the carpets, and a professional detail is your best option.
Rotten eggs are a classic telltale smell. Unless you’ve forgotten a carton of eggs in the trunk for a few weeks, the problem is likely your catalytic converter. Your mechanic will be able to tell you if repairs are possible or if you require a replacement catalytic converter.
Sweet smells usually indicate that something is wrong with the coolant system, as antifreeze has a distinctively sweet smell. If the coolant is leaking into your cabin, the problem most likely has to do with the heater core, otherwise, it could be a hose, the radiator, thermostat, water pump, or possibly head gasket. Check for puddles under your car after driving, and get to a mechanic as soon as possible. Running out of coolant can result in an overheated engine, which is very bad news!
The smell of burning rubber is probably due to a slipping belt, loose hose, or a trapped plastic bag under the car (unless you’ve been doing burnouts, then it’s probably that). Check under the car for a plastic bag trapped against your exhaust system, inspect and tighten the belts and hoses, and head to a shop if you can’t find anything.
The smell of burning oil most likely has to do with your engine oil. Your mechanic should be able to quickly diagnose the issue and get you back on the road.
The smell of burning carpet or fabric could indicate a brake issue. If you notice these smells, get to a shot as soon as you can, ESPECIALLY if you’ve noticed reduced performance in braking.
People often describe the smell of electrical problems as “burnt toast”. Electrical problems can be a huge nuisance but are usually relatively easy to fix once they’ve been tracked down. Get to your mechanic and tell them it smells like breakfast.
This smell could be the result of a rodent crawling up into your engine bay to find a warm place to sleep at night. These little creatures often chew wires and hoses and tend to find the smallest nooks and crannies to curl up in. Typically, they don’t survive the next time you drive the vehicle. Check under the hood and use a flashlight to find evidence of rodents – telltale signs include nests made of torn fabric and lawn debris and stashes of nuts and seeds.
Exhaust Smell in the Cabin
The smell of exhaust is most likely due to a faulty exhaust system. While this won’t have an immediate impact on your vehicle’s performance, exhaust fumes are extremely toxic. Get to a mechanic as soon as you can, and consider driving there with the windows open.
Get Rid of the Smell Once and For All
Most smells will disappear once the cause has been dealt with, however, sometimes an annoying smell can persist even after the root cause is fixed. For example, fixing a busted heater core will prevent additional coolant from leaking into your cabin, but the smell may persist from the coolant that’s already leaked. Once your mechanic has fixed the underlying cause of the smell, your local professional detailer will be able to take care of any residual smells.