Replacing the timing chain is a complex procedure that can result in severe engine damage if not performed correctly. Do not attempt this without significant experience in this type of repair; consult an expert if uncertain. Ensure all work is double-checked for accuracy before attempting to start the engine. Before removing the timing chain(s) from their sprockets, verify that all sprockets have timing marks. This procedure requires three special tools (EN 48383-1, 48383-2, and EN 48383-3) available through SPX Tools. Proceed with the following steps assuming the engine, subframe, and transaxle assembly have been removed. Start by disconnecting the negative battery cable, draining the oil, and removing the oil filter. Remove the spark plugs for easier engine rotation, the drivebelt and tensioner, intake manifold, valve covers, water pump, power steering components (without disconnecting lines), alternator, crankshaft pulley, Camshaft Position (CMP) sensors, camshaft position actuator valves, engine mount bracket, drivebelt idler pulley, and thermostat housing. Remove all timing chain cover bolts, using a bolt near the water pump to release the cover from the engine block, and carefully pry it away from the block. Rotate the crankshaft to align the primary timing chain sprocket mark with the oil pump housing mark in the 5 o'clock position. Install special tools on camshafts, remove timing chain tensioner bolts for the rear cylinder head, and carefully remove the tensioner. Remove the rear cylinder head timing chain guides and chain, then the special holding tools from the camshafts. Repeat this process for the lower or primary timing chain on the front cylinder head. Inspect components, cleaning and replacing as necessary, and reset the tensioners. Installation involves aligning the crankshaft sprocket with the woodruff key, ensuring timing marks align, and installing special tools on the camshafts. Install timing chains, guides, and tensioners, making sure all timing marks are correct, and remove camshaft retaining tools. Rotate the crankshaft to align the sprocket mark with the oil pump housing mark in the 9 o'clock position, install special locking tools on camshafts, and proceed to install the rear cylinder head timing chain. Install inner and outer guides, a new gasket for the tensioner, and the tensioner itself. Repeat this process for the front cylinder head's primary timing chain. Carefully clean the timing chain cover, apply RTV sealant, and slide it over the crankshaft, using aligning studs before tightening cover bolts. Complete the installation in reverse order, ensuring proper engine rotation before attempting to start it.
Posted by GMPartsGiant Specialist