GM 12638426
Camshaft

To replace the Camshaft, one first collects tools - include a wrench set, a Camshaft, and an oil filter, amongst others. Front and rear cover alignment tool (F&R) a5692-a. Start with the removal of the engine assembly, crankshaft balancer, oil level indicator tube, left and right exhaust manifolds, water pump, intake manifold, engine valley cover, coolant air bleed pipe, and left and right valve Rocker Arm covers. Then remove the valve rocker arms and push rods, left and right cylinder heads, and valve lifters. Remove the Oil Pan to front cover bolts and the front cover bolts and remove it by removing them, the front cover and gasket, disposing of the old gasket. Spin the engine to have the timing marks on top of each other, then take out the Camshaft sprocket bolts and Timing Chain from Camshaft sprocket. After that, remove the Camshaft. During installation, install the new Camshaft and align the Camshaft sprocket alignment mark to the 6 o'clock part, then install Camshaft sprocket and Timing Chain. Torque the Camshaft sprocket to 25 n.m (18 lb ft), apply a 5mm (0.2 in) bead of sealant measuring 20mm (0.8 in) in length to the Oil Pan to engine block junction and install the front cover with a new gasket. Tighten the front cover bolts and Oil Pan-to-front cover bolts without tightening them completely and tighten the j 41476 crankshaft balancer bolt to the front cover with its tapered legs aligned to the machined alignment surfaces. Tighten the crankshaft balancer bolt until hand tight and do not overtighten, then tighten the Oil Pan-to-front cover bolts and engine front cover bolts with the torque in the range of 25 n.m (18 lb ft). Remove the j 41476 and install new crankshaft front oil seal and then reinstall valve lifters right and left cylinder heads, valve rocker arms and push rods, and right and left valve Rocker Arm covers. Last, install the air bleed pipe for the coolant, intake manifold, water pump, left and right manifolds for exhaust, oil indicator tube of the level, crankshaft balancer, and also assemble the engine.

Apply a 5 mm (0.2 inch) bead of sealant GM P/N 12378190, or equivalent, 20 mm (0.8 inch) long to the oil pan to engine block junction.

Install the crankshaft balancer bolt until snug without overtightening.

Install the camshaft sprocket bolts and tighten to 25 Nm (18 lb ft).