My wife has 2000 X5 3.0i and the front end bushings needed replaced. I ordered and took two weeks to find time to change. While we were waiting for the time and parts I instructed her to not drive and so it was parked for the two weeks. Easy rebuild on the front end and went to drive in for the alignment and there is a random knocking on the top of the engine. The knocks are 1, 2 , 3 , 2, 1. No pattern but a knock not a ticking. New to BMW the car has 157k and was tight and quiet before parked. Any ideas? Thanks much for your time.