Re: 535i intake gasket problem
Talked to an older BMW master tech last night and here is the probable scenario.
I reused the old wave washers which had lost some of their spring. Over time the length of the intake and the heat/cooling cycles makes the outer cylinders flex a bit which with the older washers made the nuts back off a bit. Eventually they back off enough to cause a slight vacuum leak which then caused a backfire, thus the blowing of the gasket to the outside. Solution, don't reuse older fasteners or washers. Rookie mistake on my part.