GM 12625986
Camshaft

The right side Camshaft replacement process starts with manifold removal of the lower intake alongside Camshaft cover sensors and position actuator solenoid and Crankshaft balancer. Use the Crankshaft rotation socket (EN 46111) to rotate the Crankshaft which allows positioning the camshafts at a low tension neutral stage while the Camshaft flats maintain parallel alignment with the Camshaft cover rail. The engine needs stable structure by using an open-end wrench to halt the hex Camshaft movement despite keeping the Camshaft position actuator bolt in position. Use the Timing Chain retention tool (EN 46108) by completely inserting it to the Timing Chain then tighten its nuts firmly until marks appear on both the Camshaft Timing Chain and Camshaft position actuators while maintaining proper alignment for assembly. Mark the Timing Chain and corresponding positions on each Camshaft position actuator before removing both the Camshaft position actuator bolt and Camshaft bearing caps and Camshaft from the engine block. To install correctly position the alignment marks on both the Camshaft position actuators alongside the Timing Chain before you skip tightening the Camshaft position actuator bolt. Begin with Camshaft alignment at the Cylinder Head. Then proceed to install the Camshaft actuators before incorporating the camshafts and Camshaft bearing caps. Install the Crankshaft balancer before using the open-end wrench at the Camshaft hex to stop rotation of components. The maintenance work ends with the installation of Camshaft position actuators accompanied by the intake Camshaft position actuator solenoid and Camshaft sensors before Camshaft cover and lower Intake Manifold attachment.

The left side Camshaft replacement process starts with lower Intake Manifold disassembly and then moving to remove the left bank Camshaft cover and the Camshaft sensors together with the Camshaft position actuator solenoid. The Crankshaft balancer needs removal before rotating the Crankshaft with the Crankshaft rotation socket (EN 46111) to position the camshafts at their neutral (low tension) orientation with flat surfaces parallel to the Camshaft cover rail. The hex-side wrench on the Camshaft serves to maintain engine and Camshaft stability but the technicians do not untighten the Camshaft position actuator bolt yet. Fully extend the Timing Chain retention tool (EN 46108) into the Timing Chain while tightly securing its nuts until both Camshaft Timing Chain and Camshaft position actuators receive proper assembly marks. Before removing the Camshaft position actuator bolt and camshafts you need to mark both the Timing Chain and respective positions on the Camshaft position actuators. The first step of installation requires timing the marks on both the Camshaft position actuator and Timing Chain to match before leaving the Camshaft position actuator bolt loose. The cylinder head should receive the camshafts after aligning them correctly while installing the Camshaft bearing caps and Camshaft actuators. Take off the Timing Chain retention tool (EN 46108) via an open-end wrench at the Camshaft hex avoiding Camshaft rotation. Assemble and snugly fasten the Camshaft position actuators before installing the intake Camshaft position actuator solenoid then the sensors and Crankshaft balancer and Camshaft cover and ending with the lower Intake Manifold.

Begin by removing the upper intake manifold along with the lower intake manifold.

Unscrew the EN-48313 to retract its legs and insert it between the camshaft actuators.

The left bank camshaft cover.

Rotate the camshafts toward each other to create slack in the chain.

The camshaft cover, camshaft sensors, and the intake camshaft position actuator solenoid.

Remove the intake camshaft position actuator solenoid.

Detach the camshaft sensors and the intake camshaft position actuator solenoid.

Mark the timing chain and camshaft position actuators for proper assembly.

Rotate the camshafts towards each other.

Remove the EN-48313, then install the camshaft position actuators.

Remove the EN-48313, install the crankshaft balancer, and use an open-end wrench to prevent rotation. Finally, install and tighten the camshaft position actuators, intake camshaft position actuator solenoids, camshaft sensors, camshaft cover, and lower intake manifold.

For installation, place the hydraulic element lash adjusters into their bores in the cylinder head and lubricate them along with the valve tips.

Position the roller followers on the valve stem tips and lash adjusters, applying the same lubricant.

Remove the hydraulic element lash adjusters.

Rotate the crankshaft with the EN 46111 until the camshafts are in a neutral position, ensuring the camshaft flats are parallel with the camshaft cover rail.

The timing chain and camshaft position actuators.

Position the roller followers on the valve stem tip and the lash adjuster, then install the exhaust camshaft and lubricate it.