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Re: Exhaust smell when heater or AC is on.

I have been a member on this board for several years and have yet to get any helpful ideas on problems with my E-24, E-34 and E-32 cars. I had decided to try one more time with this last post regarding exhaust type smells from my heater. Is this mostly a "social gathering" site, or are there really some good, seasoned techs here with experience on older models? I am beginning to wonder.

Exhaust smell when heater or AC is on.

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.