#10. Remove the spark plugs. 16mm Socket? First, blow compressed air into the spark plug holes to keep debris from falling into the cylinders when you remove the spark plugs.
Old (40,000 mile) Bosch Platinum +2 Plugs, plus the BMW spark plug socket. You can see the oil leak residue (hex part) on the second spark plug from the right. That didn't leak 40,000 miles ago...