To take the rocker arms off you must take the valve cover off. They come off 4 at a time.

The motor will try to turn when you add air. If its locked up that won't happen but any vavles in the open position will leak. So by removing the rockers the cylinder should be sealed.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician