On Vehicle: Removal
- Remove both cylinder head covers. Refer to COVER(S), CYLINDER HEAD, REMOVAL AND INSTALLATION .NOTE:
Only remove the camshafts from one head at a time. The opposite head must remain assembled in order to lock the crankshaft against rotation.
NOTE:If the rocker arms are to be reused, identify their positions so that they can be reassembled into their original locations.
- Remove the rocker arm(s). Refer to ROCKER ARM, VALVE, REMOVAL AND INSTALLATION .CAUTION:
Air pressure applied to the cylinder holds the valves in place. This air pressure also has a tendency to force the piston down and rotate the crankshaft. Do not allow the crankshaft to rotate. Crankshaft rotation may damage the timing chain or front timing cover and affect camshaft timing.
- If removing the RH camshafts, install the (special tool #2025101090, Holder, Camshaft Phaser - Left-Front Cyl Head) (2) to lock the crankshaft against rotation.
- If removing the LH camshafts, install the (special tool #2025102090, Holder, Camshaft Phaser - Right-Rear Cyl Head) (2) to lock the crankshaft against rotation.NOTE:
Number 4 cylinder intake valve spring compression shown in illustration, all other valves similar.
- Remove the spark plug. Refer to SPARK PLUG, REMOVAL AND INSTALLATION .
- Install Valve Spring Compressor (special tool #MD998772A, Compressor, Valve Spring) (2) onto the cylinder head.CAUTION:
Air pressure must be maintained as long as the valve springs are removed to prevent the valves from dropping into the cylinders.
- Install a spark plug adapter attached to a regulated shop air supply (1). Pressurize the cylinder being serviced to 620.5 - 689 kPa (90 - 100 psi) to hold the valves in place.
- Using Valve Spring Compressor Adapter (special tool #10224, Adapter, Valve Spring) (3), compress valve spring (4) and remove valve retaining locks (5).NOTE:
If the springs are to be reused, identify their positions so that they can be reassembled into their original locations. Number 5 cylinder exhaust valve spring shown in illustration, all other valve springs similar.
- Release the valve spring compressor and remove the valve spring retainer (1) and valve spring (2).
- If required, remove the valve guide seal and spring seat. Refer to SEAL(S), VALVE GUIDE, REMOVAL AND INSTALLATION .
