The camshafts and Lash Adjusters should always be thoroughly inspected before installation, and camshaft endplay should be checked prior to removal. Begin by detaching the cable from the negative terminal of the battery, then remove the valve covers. Next, remove the
Timing Chains and camshaft sprockets; for 2004 and later models, unbolt the camshaft position sensor from the rear end of each cylinder bank if necessary, ensuring the working end of the sensor does not touch metal after removal. Mark the camshaft bearing caps from 1 to 4, indicating intake or exhaust with an "I" or "E," and mark arrows to show the front of the engine. Loosen the camshaft bearing caps in two or three steps, following the reverse order of the tightening sequence, while keeping the caps in order for reinstallation. Remove the bearing caps and camshafts, noting the camshaft markings for correct installation. Remove the Lash Adjusters and shims from the cylinder head, keeping the proper shim with each Lash Adjuster and maintaining their order for reinstallation. Inspect the camshaft and Lash Adjusters before proceeding with installation by placing the Lash Adjusters and shims back into their original locations. Apply moly-based engine assembly lubricant to the camshaft lobes and journals, then install the camshafts in their original positions with the dowel pins facing up and inline with the cylinder bank. Apply a bead of RTV sealant to the sealing surfaces of the No. 1 bearing cap(s), then install the bearing caps and bolts, tightening them hand tight before tightening the bearing cap bolts in several steps to the specified torque. Install the camshaft sprockets and timing chain, holding the camshafts with a suitable wrench while tightening the sprocket bolts to the specified torque. The remainder of the installation follows the reverse order of removal, and if any part of the valve train was replaced, check and adjust the valve clearance.