If your vehicle is giving off an unusual or sickening odour, check around the car for possible causes. Bad smells can lead to expensive repairs or health hazards and shouldn’t be ignored.
Here are some common bad car smells and their possible causes:
Your brakes or clutch need attention
Associated smell: Acrid
When it smells: Usually when the vehicle is moving, or when the brakes or clutch are applied.
Why it smells: Harsh, acrid smells typically mean that either brake or clutch material has been burnt. Riding your brakes or leaving the parking brake on are both great ways to make your car smell like this.
A burnt clutch smells very similar to brake pads that got too hot, and it can be caused by riding the clutch. It can also mean that your clutch is slipping, either because it’s worn or because it needs adjustment.
What to do: If the smell persists and you haven’t been driving in stop-and-go traffic or on long downgrades, have your brakes inspected.
Your radiator or heater core is leaking
Associated smell: Sweet, maple syrup
When it smells: The heater is turned on, the engine has warmed up, or sometimes after you shut the engine off.
Why it smells: If your engine has been running for a few minutes and you start to smell something sweet, coolant containing ethylene glycol could be leaking from the radiator, cylinder head or a failed intake manifold gasket.
If the smell is strongest inside the car, this is could indicate a problem with the heater core. In both cases, you’ll need to have a mechanic look into the issue.
What to do: If coolant is leaking, you could damage the engine by driving. Have your vehicle towed to the nearest repair shop.
Water is getting where it doesn’t belong
Associated smell: Musty
When it smells: All the time, or after a rain.
Why it smells: A mouldy or mildewy smell indicates that water is getting in your car and then pooling there. Leaky door or window seals can allow water in, so if you find wet seats or carpeting, then that’s probably the issue.
If you turn on the heater or air conditioner and it smells like a musty basement, you could have mildew growing inside the AC evaporator.
What to do: In some cases, running the fan with the vents open and the a/c off helps to dry it out, but you may need to have your system cleaned by a professional.
You have an oil leak
Associated smell: Burning oil
When it smells: The engine is hot, whether or not you’re driving.
Why it smells: When oil drips on any part of the exhaust system, it burns. This smells really bad, and it can also create thick, blue smoke if the leak is bad enough. You should get rid of the leak.
What to do: Take your car back to the mechanic and have it checked.
Your catalytic converter is busted
Associated smell: Rotten eggs
When it smells: The engine is running.
Why it smells: Your catalytic converter is designed to convert hydrogen sulphide in your engine’s exhaust into sulphur dioxide. The rotten egg smell could signal that the catalytic converter isn’t working as it should be replaced. If it’s a newer car, this repair could be covered by your warranty.
What to do: Take your car to a mechanic as soon as possible.
Gas is getting where it doesn’t belong
Associated smell: Gas
When it smells: All the time, when the engine is running
Why it smells: If you smell gas fumes after the engine is warm, though, the gas cap could be loose or the evaporative emissions control system could be leaking or clogged. Even worse, gas could be leaking from the tank or another part of the fuel system, such as the fuel line. Always investigate gas smells you discover when your car is parked before starting the car and potentially igniting the fuel.
What to do: Pull over safely and turn off the engine immediately. Get your car towed to the auto shop.
Slipping belts or overheating rubber
Associated smell: Burnt rubber
When it smells: Whilst driving
Why it smells This may be the result of an engine belt that’s slipped. It could also be a hose from the cooling or power steering system that’s rubbing on a belt and has started to melt.
What to do: Wait until your car cools down, then open the hood and inspect your belts and hoses. If the smell persists, take the car in to be checked out.
Short circuit or overheated insulation
Associated smell: Burning plastic
When it smells: Whilst driving
Why it smells: A major cause of burning smell from the car is the electrical short circuit in the engine. The plastic coating on wires, fuses, or other connections may produce the smell. So the smell would be similarly with the burning plastic smell in the car. Take electrical odours seriously, because short circuits and overheated components are common sources of fire.
What to do: Take your vehicle in for diagnosis and repair.
Your groceries rolled under the seat
Associated smell: Rotting fruit
When it smells: After you get home from the grocery store and notice missing groceries.
Why it smells: Look in pockets, under seats, or on floor mats for baby bottles in the back seat, mouldy fruit in forgotten bags or unidentified blobs that may have been dragged in on the bottom of someone’s shoe.
What to do: Be sure to clean the affected areas to clear out any resulting bacterium.
Someone has been smoking in your car
Associated smell: Smoke
When it smells: All the time
Why it smells: This one is more obvious than the others, and you probably already know why it smells. Smoke from cigars and cigarettes represents one of the most persistent bad car smells. Even special measures, like smoking with the windows rolled down, doesn’t really help that much. Smelly remnants settle into the carpet and upholstery, coat the windows and dashboard, and no amount of air fresheners will help.
What to do: Clean the ashtrays. Sprinkle some baking soda on the carpet and upholstery and leave it for an hour. It can help absorb odours as you vacuum it up. If the problem persists, book your car for an air-conditioner treatment. It will not only remove the cigarette smell but will eliminate micro-organisms such as fungi, bacteria, mould and mildew.
Bad smells can lead to expensive repairs or health hazards and shouldn’t be ignored. If you notice any of the above smells find the source of car odour, treat it, and your car should smell great.