[Phil@BPC]

Hey guys here are some photos I took during a tear down of an F10 that came in. Customer brought this M5 in because of a really bad sound coming from the engine. Surprisingly a check engine light never came on or a warning message. Once we brought it into our center we could hear the noise right away. Once we looked over the car and made sure everything externally was ok we performed a compression test. During this test we found cylinder 5 to be the culprit. We pulled the drivers side cylinder head and removed piston/ rod combination from cylinder 5. Hope this sheds light on something that's rarely seen.
































































Only very minor scoring on the cylinder walls. Most impressive is that the cylinder bore has a bend about half way facing the passenger side.







The culprit... still amazing this didn't set a check engine light or any malfunction warning messages.