GM 1645821 Cylinder Head (Machine'D)

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To remove and install the cylinder head on a 4.5L or 4.9L engine, start by disconnecting the negative battery cable and draining the engine coolant. Remove the rocker arm covers, lower intake and right side exhaust manifolds, engine lift bracket, and oil dipstick tube. Reposition the AIR bracket and remove the cylinder head bolts to take off the cylinder head. Clean the sealing surfaces and bolt holes before installing a new head gasket over the dowels on the cylinder block. Install the cylinder head and tighten the bolts in the specified sequence and torque. Reinstall the engine lift bracket and AIR bracket, followed by the lower intake and right side exhaust manifolds, and rocker arm covers. Fill the cooling system, reconnect the negative battery cable, and check for leaks after starting the engine. For the left side, follow similar steps but remove the intake manifold, exhaust manifold, and AIR bracket before removing the cylinder head. Clean the gasket mounting surfaces and install the new head gasket before reinstalling the cylinder head and tightening the bolts. Finally, reinstall the AIR bracket, dipstick tube, exhaust manifold, lower intake manifold, rocker arm covers, and fill the cooling system. For the 4.6L engine, it is recommended to remove the entire powertrain and utilize the cradle as an engine-stand for easier cylinder head removal. Remove various components such as the intake manifold, camshaft covers, harmonic balancer, front cover, and oil pump before removing the cylinder head. Clean the gasket surfaces and combustion chamber before installing the new cylinder head with the specified torque for the bolts. Install the camshafts, set the camshaft timing, and install the remaining components before reinstalling the powertrain assembly.

To remove the cylinder head on a 4.5L or 4.9L engine, start by disconnecting the negative battery cable and draining the engine coolant. Remove the rocker arm covers, lower intake, and right-side exhaust manifolds, engine lift bracket, and oil dipstick tube. Reposition the AIR bracket and remove the cylinder head bolts to take off the cylinder head. Clean the sealing surfaces and bolt holes before installing a new head gasket over the dowels on the cylinder block. Install the cylinder head and tighten the bolts in the specified sequence and torque. Reinstall the engine lift bracket and AIR bracket, followed by the lower intake and right-side exhaust manifolds, and rocker arm covers. Fill the cooling system, reconnect the negative battery cable, and check for leaks after starting the engine.

Refinishing and repairing cylinder head components may require machine shop assistance, such as refacing valves, replacing guides, and machining seats.

Cylinder heads contain valves, guides, seats, and valve springs.