Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show


I’m Theresa from Denver and I have a 2001 Nissan Sentra. I have noticed that when I have the heater running and I stop for any amount of time, say at a traffic light, my car smells heavily of fumes inside. I took it to the mechanic to have the air filters replaced but that didn’t help. Any ideas?

What kind of fumes? If it smells like exhaust, then there may be a leak in the exhaust system. If it’s a sweet smell than the heater core is leaking.

Breathing exhaust or antifreeze fumes is unhealthy. Either situation needs to be remedied for the sake of your own health.

Ed B.

In addition to what edb wrote, an exhaust smell can be very dangerous. Please drive with your windows open until it is corrected.

Did you tell the mechanic about it? Did the mechanic smell it? Or did you just think maybe you needed new air filters and just asked to have them replaced?

Someone who knows what they are doing needs to find the issue asap.

Filters don’t stop fumes, which are vapors. It could be raw fuel fumes, exhaust fumes, or coolant fumes. None of which are good. You need to find and fix the source of the “fumes” quickly.

Coolant is a “sweet” smell and often you get a coating on the inside of the windshield if you use defrost mode on your heater. That means the heater core (essentially a small radiator) is leaking. Can be expensive on many cars.

Exhaust fumes you should know. Until fixed keep a window open at least a “crack” to make sure you have good air to breath. This is usually a rotted out exhaust pipe, or muffler. Not too expensive to fix.

Raw gas fumes can be sucked into the cabin when the heater fan is on. Raw gas fumes are dangerous, can you say explosion, or engine compartment fire? If you have smelled fumes when refueling your car you know the smell of raw gas fumes. A leak in a fuel line can contact hot areas of the engine and gas fumes result, very dangerous.