burning smell coming from vents

[RAngcoNY]

Hi, I need some advice. When I turn the heater on I smell something burning (or exhaust). It doesn't happen all the time. It comes and goes and it doesn't matter which vents are being used whether it is the floor, front or dashboard vents (defroster). The temperature does work; meaning it gets hot when I turn it up and cools when I turn it down. Again, I don't smell it all the time but the smell is there often. Thanks in advance!

2007 328xi sedan / E90

[ElRedOne]

Does it smell like burning oil? You may have a small leak that is dripping on a hot engine and burning, the fumes for which are being drawn in to the HVAC system.

[RAngcoNY]

Does it smell like burning oil? You may have a small leak that is dripping on a hot engine and burning, the fumes for which are being drawn in to the HVAC system.

Come to think of it, it smells like exhaust; not burning oil. Occasionally a blast of exhaust smell comes through the vents. order so strong I need to turn off blower and open windows. a few minutes later, turn blower on and no smell. a day or 2 later, same thing..out of nowhere, blast of exhaust smell enters the cabin.

there are no trucks or buses in front of me...it happens at odd times.

Any ideas?

[RAngcoNY]

My mechanic found the issue. replaced evap pump (it was throwing a fault code and ses light on).

Light/code were reset and exhaust order is gone. $205 installed

[ndog14]

Cabin air filter?

If you smell what I think it is and what I have smelled it is your power steering. I read that occasionally you can get that smell in an E9X.

[RAngcoNY]

Cabin air filter?

If you smell what I think it is and what I have smelled it is your power steering. I read that occasionally you can get that smell in an E9X.

Hmm power steering. hadn't thought of that. My mechanic said to rid the order, go to dealer and buy the 'vent spray' ($30). remove cabin air filter and spray. i guess its a deodorizer or something.

[Level1Tech]

are you sure your valve cover gasket isn't leaking?

[jrose7004]

I had that problem when my valve cover gasket needed to be replaced. Soon you'll have oil on the garage floor.

[Saltql]

+1 on valve cover gasket