For this procedure, one needs a special valve spring compressor from aftermarket specialty tool manufacturers, as the only other way to perform the task is to remove
Timing Chains and camshafts and leverage major engine dismantling. This is a non-freewheeling (interference) engine, and in order to compress the assembly of the valve and spring, the pistons have to be down in the cylinder bore. Before starting ensure the transmission lever is in Park, the handbrake is engaged, and the ignition coils together with spark plugs are out of the engine. Lift off the valve cover(s), and give an identification to those rocker arms and lash adjusters for reference during reassembly. Slowly turn the engine clockwise by the crankshaft pulley/vibration damper bolt turning until pistons are exactly in position for removal of rocker arms beginning with number 1 on the TDC Compression. Note the following pattern for removal of these rocker arms: cylinder No. 2 and 6, cylinder No.1, cylinder No. 3 and 5, and at last cylinder No. 4 for the 3.7L V6 engine . For the 4.7L V8 engine, the specified rocker arms to be removed are those of cylinder No. 2 and 8 followed by cylinder No. 3 and 5, cylinder No. 4 and 6 and cylinder No. 1 and 7. To take out the rocker arm, utilise the valve spring compressor to reduce tension on the rocker arm. When replacing only several rocker arms or lash adjusters, find the corresponding cylinder and turn the crankshaft correspondingly; make sure to keep parts together to reinstall them. Pull out the lash adjusters and check such parts as the rocker arms for any sign of wear or damages, they should slide past one another. Removal of the installation is again the complete process of installation in the reverse order, except that the lash adjusters should be only partially filled with oil to reduce the strokes of the plungers.