The Nissan Path

Hi all, what could cause an exhaust smell from the vents into the cabin? We recently had an oil leak (o-ring replaced), although I doubt that's related. The car was checked and serviced by a Nissan dealer, but the odor remains whenever we run the heater/fan, recirc or not. Any ideas? Thanks....

have u tried changing the cabin filter ?

if any smoke was coming into the cabin at that time, the filter couldave absorbed the smell.

remove the filter, open vents to allow outside flow, run it full blast with all windows open and replace with new filter.