Please remember that in engines 934.9 and 936.9, the valve clearance of the intake valve has been changed from 0.40 mm to 0,30 mm. The maintenance interval has also changed.
Previous maintenance interval: Adjust valve clearance (at 1st, 4th, 7th, 10th etc. engine maintenance)
New maintenance interval: Adjust valve clearance (at 2nd, 4th, 6th, 8th etc. engine maintenance)