We’ve probably all had this happen; we’re cruisin’ on down the road, when suddenly we smell it - a foul odor emitting from our car like burnt toast or worse yet, rotten eggs. Unfortunately, sudden odors and foul smells generally signal there is a problem, so don’t roll down the window and hope it goes away, because it won’t.  In fact, chances are that unless the source of the odor is verified and repaired, it will only get worse, resulting in a potentially more expensive repair bill.

Here are some odors you should be aware of and what they can mean. Keep in mind that if you start to smell a sudden, strong odor and you can’t find it with a quick check under the hood, the best solution is to visit to your dealer or mechanic as soon as possible.  Remember that most odors and foul smells signal a much needed repair -so the sooner, the better. 

If you smell this (and when you do, you wont easily forget it because it’s awful!), it generally signals a problem with the catalytic converter, but it can also be a problem with fuel injection.  You can also smell this odor when the heater core (part of your car’s heater that takes heat from the engine) gives out.

This smell often signifies a coolant leak, the second most important fluid in your engine, after oil.  Since coolant contains ethylene glycol, which may smell sweet but is highly toxic, a faulty radiator leak, a leaky radiator hose, or even a bad manifold with a worn gasket can produce this kind of smell.  Another possible source is the heater core, which you’ll want to repair as soon as possible - especially in the winter months.  If the heater core goes bad, not only will your car be without heat, but your defroster will fail to produce any warm air to clear your windshield.

Definitely not a good smell – or sign at all.  This generally means there’s a gas leak somewhere, perhaps in a fuel injection hose, fuel tank or somewhere else.  If you’re smelling gasoline, you’ll want to take your vehicle in to see your dealer or mechanic immediately and avoid driving the vehicle until it’s repaired.  Remember leaking gas could lead to an engine fire.

This usually signals oil that has leaked onto hot portions of the engine. If you have recently put oil in your car and spilled a little bit, this smell is okay.   The smell will go away in a few minutes after the oil burns off, however if the smell suddenly occurs or persists, it could mean a leaky seal or something else. The best thing to do is look to see if oil has pooled up underneath your vehicle or is dripping steadily, and if so, it’s time to visit a mechanic.

This usually means there’s a problem with the exhaust system, therefore it should be checked out by a mechanic as soon as possible.  Exhaust fumes contain carbon monoxide and are dangerous. Breathing exhaust fumes can make you sick, causing nausea, headaches, a light headed feeling as if you might pass out.  Strong exhaust fumes in an enclosed area can even result in death.  If you are smelling exhaust fumes, roll down or crack your window to let in fresh air and make sure all your air vents are closed.  Exhaust leaks require your immediate attention, so take your vehicle to your dealer or mechanic as soon as possible. 

Open the hood and check to make sure all hoses and belts are secure. Sometimes this smell indicates a hose resting on a hot engine or signals a belt, has become loose or is about to break.