7 Car Smells and What They Mean


It may mean a serious or costly mechanical issue, depending on the odor.

Everyone loves that new car smell, right? Well, if you don’t keep up on maintenance, your car could start producing some less savory smells instead.

Being aware of the smells your car produces can help you diagnose problems before you see them or before they become irreversible.

Car Smells You Can’t Ignore:

1. Rotten Eggs

The gasoline that fuels your car contains trace amounts of sulfur. This creates a by-product called hydrogen sulfide, which smells like the eggs you forgot in your trunk for a week after grocery shopping.

The catalytic converter is a crucial part of your exhaust system because it takes this by-product and converts it into odorless sulfur dioxide. If you start smelling rotten eggs when your car is running, your catalytic converter needs to be replaced. Unfortunately, this is usually a pricy fix, but it may be covered under warranty.

2. Maple Syrup

If you’re walking around your car and you get a whiff of maple syrup, you could be leaking coolant. Coolant contains ethylene glycol, which smells sweet but is actually very toxic.

The fix could be as simple as tightening a loose radiator cap or replacing a hose or gasket. If you notice the smell inside the car, it’s likely that you have a bad heater core.


3. Fire and Brimstone

You can relax; it’s not the end just yet. What you smell is sulfur from a leaky gear housing or transmission. The gear lube in these components of the drive train contain sulfur compounds that act as extreme pressure lubricants.

Over time, the lube will start to deteriorate and even leak, emitting a sulfur smell. You can check for a leak by inspecting any oil substance left behind by your car. If it smells like sulfur, it’s time to visit your mechanic.

4. Burning Moldy Newspaper

If you smell a smoldering, moldy newspaper, you’re either passing by a millennial spring-cleaning bonfire or you’ve got clutch problems.

The smell results from friction material actually burning off the clutch as it slips. If you smell this under normal driving conditions, your clutch is failing and needs to be replaced.

5. Gas Station

The only time the smell of gas should be in the air around your car is when you are refueling. A questionable gasoline odor coming from your car is an indication of a leak. The most likely culprits are a fuel injection line or fuel tank vent hose.

6. Locker Room

We all remember what the high school gym locker room used to smell like, and you probably thought you left it behind for good. However, your A/C unit could have other plans.

If you smell that familiar sour dankness in your cabin, it probably means there’s mildew in your A/C vents. There are a few ways to solve this problem, the simplest being running air through the vents with the A/C off. If you can’t dry it out yourself, it’s best to have a technician take care of it for you.

7. Burned Carpet

If you smell burned carpet while you’re driving, your brake pads are overheated. While this is normal under intense braking conditions like driving down a mountain pass, you shouldn’t smell this under typical driving conditions.

The most common cause for this is a seized caliper piston, but brakes can overheat for a number of reasons. Maintaining your brakes is the best way to avoid problems like these.


There are many smells in this world, some good, some bad. Whether we like it or not, we get to experience them all. If your car is in good health, it should be emitting no smells, at least none that are abhorrently unpleasant. Being aware of what the bad smells are and what they mean can help you diagnose a problem before it gets worse.