Is the odor stronger when you are in recirculating mode on the ventilation? If so, the heater core or its immediate connection points are most likely. If not, you're picking up the odor from under the hood from a point where the airstream can get it to the cabin filter inlet. I would actually inspect the radiator and expansion tank as possible culprits then.


2002 X5 3.0 387,000 miles
2014 428i 74,000 miles


2004 325i sold at 123,600 miles
2001 325i sold at 66,000 miles


1970 Firebird Under restoration