Five Engine Smells You Should Never Ignore

You’re driving along and you smell something funny coming from the engine. You’ve noticed the odor before. Should you worry about it? The short answer to that question is yes; you should never smell odors coming from your vehicle’s engine. Still, some odors indicate a temporary hiccup while others signal a serious problem. York Tire & Auto Service can help you decipher the engine smells below.

1. Sulfur (Rotten Eggs)

The reason why we put rotten eggs in parentheses is that sulfur smells like rotten eggs. If you smell rotten eggs coming from your car, truck, or SUV’s engine, your catalytic converter is going bad. This is serious, because the catalytic converter is the exhaust system part that takes carbon monoxide and turns it into the much safer carbon dioxide before it’s released through the tailpipe.

2. Maple Syrup

We don’t mean to get into a food theme here, but coolant often smells like maple syrup. Engine coolant smells sweet, and it’s the ethylene glycol in the coolant that gives it that syrupy odor. If you smell something sweet coming from your engine, you may have blown a cylinder head, your radiator might be leaking, or could have problems with the intake manifold gasket. The heater core could also be leaking.

3. Burnt Paper

This only applies if you drive a vehicle with a manual transmission. If the clutch facing is burning, you will get a whiff of burnt paper each time you shift gears. Friction causes the clutch facing to burn, so make sure you don’t ride your clutch or step on the clutch pedal more than is necessary. The reason why the clutch facing smells like burning paper is that there is a paper-based layer on the facing.

4. Hot or Burning Oil

If you smell hot or burning oil from your engine, this does not necessarily mean your engine is burning oil. The engine will smell like burning oil when it’s overheating, which could actually be a coolant issue, or when the transmission is overheating. Oil leaking onto the exhaust manifold or engine will cause a burning oil smell, as well, but this odor no matter the cause is a sign of serious engine trouble.

5. Musty/Mildew

Finally, as with your home’s heating and air-conditioning unit, your automobile’s heater and air conditioner can end up with mildew growth inside the evaporator. When you turn on the heater or AC, you’ll get a musty odor flowing into the vehicle cabin through the vents. Using the fan regularly without the AC on helps keep the evaporator dry and prevents mildew growth.

Call York Tire & Auto Service in Red Lion, PA, if you notice any strange engine smells coming from your car. We will find the problem and fix it.

Photo by AndreyPopov via

Accessibility Toolbar