THE MERCEDES-BENZ OM654 1.6L AND 2.0L DIESEL ENGINES USE A TIMING CHAIN THAT IS MOUNTED AT THE BACK OF THE ENGINE WHICH MEANS ANY TASK INVOLVING ITS REMOVAL WILL REQUIRE THE ENGINE TO BE REMOVED. ONCE THE ENGINE IS REMOVED THIS TOOL ALLOWS THE USER TO LOCK THE CAMSHAFTS AND CRANKSHAFT IN THEIR TIMED POSITION FOR CHAIN REPLACEMENT. NOTE: THE TOOL CAN ALSO BE USED TO LOCK THE CAMSHAFT AND CRANKSHAFT WITH THE ENGINE IN THE VEHICLE WHEN CHECKING THE TIMING.