I've had a sweet smell come through the vents at start up about a half dozen times in the last few weeks. I know it is related to the cooling system, but there is no leak, overheating, or reduction in radiator fluid level. Anyone had this happen before?

I have an appointment to drop it by the dealer this week, but I doubt they'll be able to duplicate the problem since it happens so sporadically. Suggestions?

 

It could be a pinhole leak in the exchange unit. Not enough to notice any fluid reduction, but enough to cause the smell. Could also be mold or something else in the core.

Let us know how it turns out.

 

In-cabin filter perhaps? They recommend changing them like every 15k miles I think. I've changed mine 3x (got almost 50k miles on mine). I wouldn't call the smell sweet though, more like musty, so probably not what you're experiencing

 

Sweetish smell is usually antifreeze (coming from the heater core, I think). Or at least every time somebody complains about it on cartalk that's about what they say.

 

Sounds like a heater core issue to me. Check with a flashlight and see if you have drips under the glovebox and smell the carpet.

 

Thanks for the ideas. I just took it to the shop, and they don't think it has to do with the cooling system (radiator). They said only hot coolant smells, so since the smell has happened when the car hasn't been started in hours, they don't know where to start. They asked me to keep the AC on recirculate and see if it happens. Then to keep it on fresh air and see if it happens. Possibly an issue with the ac system.

We'll see what happens. Thanks again for the responses. Let me know if y'all know of anything I should be looking out for.