Hummer H3. Manual — part 313

Fig. 119: Removing Special Tool
Courtesy of GENERAL MOTORS CORP.

18. Lift the vehicle and remove the EN 46547 . See Special Tools.

19. Lower the vehicle.

20. Remove the J 44221 from the back of the camshafts. See Special Tools.

2007 Hummer H3

2007 ENGINE Engine Mechanical - 3.7L - H3

Fig. 120: Installing Wedge Tool Handle
Courtesy of GENERAL MOTORS CORP.

21. Install the handle of EN-48464 and remove the wedge portion of the tool from the engine.

See Special Tools.

NOTE:

Ensure that the wedge tool is removed from engine prior to
rotation. If the wedge tool is not removed, engine damage will
result.

2007 Hummer H3

2007 ENGINE Engine Mechanical - 3.7L - H3

Fig. 121: Rotating Engine Clockwise
Courtesy of GENERAL MOTORS CORP.

22. Rotate the engine clockwise by hand two complete revolutions to TDC number 1 on the

compression stroke. Use the First Method or Second Method for TDC. If you go past TDC,

IMPORTANT: It is critical that the engine is at TDC and not a couple of

degrees off. If in doubt, repeat this step.

2007 Hummer H3

2007 ENGINE Engine Mechanical - 3.7L - H3

rotate the engine back approximately 45 degrees before TDC and then rotate clockwise up
to TDC to ensure that the timing chain is tight (no slack) between the crank sprocket and the
timing gears.

Fig. 122: Installing Camshafts
Courtesy of GENERAL MOTORS CORP.

23. Both intake and exhaust camshaft flats should be facing up and flat and level with the

cylinder head. If J 44221 is used to verify cam timing, you could be off approximately one
tooth and cause DTC P0017 to set. See Special Tools. If a worn or new J 44221 is used to
verify timing, the timing will be off. See Special Tools.

IMPORTANT: DO NOT use the J 44221 , installed to the back of the

camshafts, as a method to verify timing. See Special Tools.

2007 Hummer H3

2007 ENGINE Engine Mechanical - 3.7L - H3