On my fiancés endeavor her car recently started smelling like it was burning oil really bad through the vents when you would use the heat and defrost. The fumes it was putting into the cabin were really bad so she's not driving it until I can get it figured out. It looked like the valve covers were leaking a little bit so changed out gaskets and that didn't help it. I don't see it really leaking oil at all it was a quart low a couple days ago so I did do a oil change and filter as well. I'm at a loss on this I've had vehicles before that have leaked/ burned oil and I've never had it come through the vents nor smelled it through the vents. You can see it smoking under the hood at night with the headlights on if you're parked and its idling. It has 177,000 miles far as I know its always been kept up on maintenance. Has anyone else had this problem? Really need to figure out what its doing its pretty unsafe right now imo. I don't want to put the car down I am a Chevrolet man but the endeavor is a good little suv and would like to keep it around.

 

***bump

 

bad valve stem seals