GM 12574519
Camshaft

The Camshaft replacement begins by emptying air conditioning pressure while draining the cooling system for replacement purposes. Start by removing the air cleaner housing assembly followed by removing the upper Radiator support while disconnecting the cooling fans electrical connection. Detach the transmission cooler lines from the Radiator while removing both the a/c line from the condenser and from the surge tank area and disconnect the lower and upper Radiator hoses from their positions near the Thermostat Housing and water pump outlet. The operation requires removal of the surge tank hose from both the Radiator and the integrated condenser/radiator/fan module. The engine work primarily requires the removal of the Timing Chain together with Camshaft sprocket before proceeding to remove valve lifters from both cylinder heads. After removing Camshaft retainer bolts and retainer it is essential to treat the Camshaft with care because the Camshaft bearings have the same diameter as the Camshaft journals. Insert three m8-1.25 x 100 mm (M8-1.25 x 4.0 inch) bolts into the front holes on the Camshaft to use them as handles for proper Camshaft removal from the block followed by removing the bolts. Clean the Camshaft and bearings before applying oil to Camshaft journals and bearings. Finally, replace the Camshaft into the engine block using the same handle bolt method. To install the retainer plate position it facing the engine block with a clean gasket surface while using m8-1.25 x 100 mm (M8-1.25 x 4.0 inch) bolts for leverage. Mount the Camshaft retainer followed by bolts and tighten them to 25 nm (18 ft. Lbs.). After seating the Timing Chain along with the Camshaft sprocket it is mandatory to install the valve lifters. The reinstallation process starts with putting back the condenser/radiator/fan module followed by surge tank hose, upper and lower Radiator hoses, a/c lines, and transmission cooler lines before reconnecting cooling fan electrical components. The procedure ends with replacing the upper Radiator support and air cleaner housing assembly together with air conditioning system recharging and cooling system filling.

Install the camshaft sprocket and timing chain, then install the camshaft sprocket bolts, tightening them to 25 Nm (18 ft. lbs.).

Tighten them to 25 Nm (18 ft. lbs.), then remove the J41476.

Remove the timing chain and camshaft sprocket, followed by the valve lifters from both cylinder heads and the camshaft retainer bolts and retainer.