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Unpleasant Odor

What can cause the emission of an unpleasant odor, that smells like sulfur?

I own a 2004 Mazda MPV LX, with 67,000 miles. From time to time, I smell an unpleasant odor that seems to be coming through the vents. It has happened 3 or 4 times in the past three weeks. Can you help?

It is not unusual for any car to emit a trace of hydrogen sulfur (that’s the chemical you smell) from the exhaust. It can happen any time the engine is under load. It is also a consequence of filling up with a tankful of bad gas, i.e., there is a little too much sulfur in the gasoline. Normally this is harmless. But exhaust gas should not come through the fresh air vents.

You have a leak in your exhaust system somewhere under the hood. Have this checked out. It is not a desirable situation.

Might you have backed the car through the car’s exhaust? If the wind wasn’t blowing, the exhaust could have, then, been drawn through the vents at the base of the windshield. Try a different brand of gasoline. It may have less sulfur.