I thought I knew these cars very well (I have owned many) but this problem has me stumped. Any time the blower is run I get what smells like exhaust coming out the vents. No, it does not smell like coolant (I have done two heater cores myself on previous cars). My mechanic friend (a 25 year factory trained Bimmer guy) and I did discover evidence that a mouse had been living in the heater box, as there was a lot of pink insulation in there. We got it all out and I sprayed the whole area with an industrial chemical which was supposed to get rid of any residual "stuff" that might be in there. The smell is still there! And it sure smells like exhaust to me. To repeat, there is no smell until the blower is run.

If there is a genius around that has a clue for me, I could sure use it. My pristene 20 year old 735i still has only 78K on the clock but this is driving me crazy. My wife refused to ride in it if we have to use the blower, even for fresh air. H-E-L-P.