All three of my cars have done this. I sounds like some sort of gate is opening and closing. Is this an area on concern? Can some maintainenace be done to eliminate it? Or is it, shall I say, NORMAL! Thank you Drew
It's the air diverter flap moving. Kinda normal considering how old the cars are. if you're really concerned about ityou could pull the dash apart and lube the stuff up.
The first time I heard it I was kind of concerned but since it has happened on subsiquent cars I don't worry about so much. How deep is it in the dash? Without attention will it fail? Thanks Drew
Most GM cars of that era flap. Vacuum door moving thingy has to overcome the stiction of the door edging that likes to glue itself to the edges. Use all the controls all of the time and the flapper will be better off and make less noise.