Funny smell from vents



I have a 1998 Lexus SC400 that runs great. Recently, there has been smell coming through the heater vents. The smell is not consistent and I can’t really find a pattern. Sometimes it occurs right away, sometimes it’s more noticeable when I’m idling. To me, it smells like I’m sticking my nose in a tin of band-aids. A friend says it smells more chemical, like paint thinner. Doesn’t smell like burning or exhaust. No new brakes. All belts have been checked. I did have the exhaust system checked as well as a fluid compression check to rule out any leaks. Lexus says to bring it in when the smell is evident which is hard to do. If I do smell it, then when I crank up the heater with or without A/C, the smell seems stronger. I’d also say that it occurs about 25% of the time. No rhyme or reason that I can assess.

Any guesses? Any other ways to narrow this down? Thanks!


Keep an eye on your coolant level. First thought is a leaking heater core. Some associated symptoms would be dampness near the passengers feet and difficulty defogging the windows. It could be a very small slow leak but typically they get worse instead of better. A visual inspection of the heater core could provide evidence of a leak, but maybe there are other ideas out there.


Agree; if the smell is either sweet (relatively fresh coolant) or a nasty sour smell or stale currie (older coolant), you can be virtually sure it’s a heater core leak.

The presence of moisture on your windshield means a sizable leak and quick failure of the core.

If is smells like decaying flesh, it would be an animal or part thereof, in your air plenum.

In any case take the car into a good shop.


You can try spraying lysol into the intake vents (with blower on), will kill any mold and help reduce odor…


Thanks for the feedback. I took my car to the Lexus dealer who did a complete check of all of the fluids and didn’t find any leaks or evidence of dripping. I just checked the coolant level and it looks good. Also, I don’t have any added moisture or inside humidity (even in Seattle!)


Open the hood, remove the cap from the windshield washer fluid reservoir and take a whiff. Does the odor through the vents smell like this? Some windshield washer fluid has a rather chemical odor. This may not be your problem, but it is easy to check.


Problem solved. I had a failure with the “Pulsation fuel damper,” which was slowly dripping gas on to the side of my engine. So far… Thanks for all the feedback.