When weird smells begin emanating from my vehicle, I first look under the seats for an old fast food bag. If the interior of the vehicle isn't the source of the smell, then I move to the engine. Smells generated by a vehicle's engine can point to potential trouble ahead. Here are six smells to be wary of and what the mechanical issues that might cause them.

Rotten Eggs or Sulfur

If you smell rotten eggs, this could be an indication that your catalytic converter may not be properly processing hydrogen sulfide in the exhaust. Take your car to a mechanic as soon as possible.

Maple Syrup

If you smell something sweet after the engine has been running for a few minutes, 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.

Burnt Paper

The smell of burnt paper while driving, especially when changing gears, might be a sign that the clutch facing is burning off as the clutch slips. This can happen if the driver is “riding” the clutch, stepping too frequently on the pedal, which causes significant friction. This friction creates enough heat to actually burn the paper-based clutch facings, which creates the smell and can cause the whole clutch to fail.

Burnt Oil

Smelling burnt oil? First, check the oil dipstick. You might be running out of engine oil or your engine may be overheating. If neither is the case, look for oil leaking onto the engine block or exhaust manifold. Next, check your transmission fluid. If it’s low, it could be burning in the transmission because the gears aren’t properly lubricated and are overheating. Also be sure that you’re using the correct type of engine oil for your vehicle. Use the Cenex Equipment Lookup feature to help you find which lubricants are recommended for your vehicle.

Musty Basement

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. Turn off the a/c and drive with the fan on high to dry the system out.

Burnt Carpet

A burnt carpet smell, especially after extensive use of the brakes, could mean your vehicle’s brake pads are overheated. Or you left the hand brake on. Take your vehicle to a mechanic to replace the worn brake pads.   

For more information on what’s happening inside your engine, check out these blog posts:

Get to Know Your Car’s Fluids

Don’t Forget Preventive Maintenance

Photo courtsey of Flickr user andrewtamala

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