When the 750iL calmly accelerates, you can here a sound like an exhaust leak from the engine. I had an exhaust shop look at it. They sniffed around with a type of sound scope and could not find a leak around the exhaust.
At an idle, if you put your ear to it, the rear of the engine sounds leaky compared to the front. Would leaks around the valves or rings make this type of sound? Ideas? Thanks.