GM Service Manual Online
For 1990-2009 cars only

Engine Description

Cylinder Block

The cylinder block is an aluminum casting with four cast iron cylinder sleeves. The cylinder block has four in-line cylinders which are numbered 1 through 4 starting from the crankshaft pulley. The cylinder block contains coolant jackets through which coolant flows around the cylinders, to cool the cylinder block and maintain a constant operating temperature. The lower crankcase of the cylinder block is also an aluminum casting with cast iron inserts at the main bearing locations. The lower crankcase runs the entire perimeter of the cylinder block.

Crankshaft

The crankshaft is cast nodular iron with eight counterweights. Oil holes run through the center of the crankshaft to supply oil to the connecting rods, bearings, pistons and other components. The end thrust load is taken by the thrust washers installed at the center number three bearing journal.

Connecting Rod and Piston

The connecting rods are forged steel, heat treated and shot peened. The connecting rod incorporates the semi-floating type pin. The pistons are cast aluminum. The piston rings are of a low tension type to reduce friction. The top compression ring is stainless steel. The second compression ring is cast iron. The oil ring is a 3-piece spring construction.

Oil Pan

The oil pan is constructed of stamped steel and is mounted to the lower crankcase. The oil pan includes a baffle that helps prevent the oil from shifting away from the oil pump suction pipe during hard turns, acceleration or stopping.

Cylinder Head

The cylinder head is an aluminum casting with pressed-in valve guides and valve seat inserts. The fuel injection nozzles are located in the intake ports.

Valves

There are two intake and two exhaust valves per cylinder. The valve springs are conical-shaped. Positive valve stem seals are used on all valves.

Camshaft

Two camshafts are used, one for all intake valves, the other for all exhaust valves. The camshafts are cast iron. The intake camshaft also has the camshaft position sensor lobe cast onto it.

Camshaft Housings and Covers

The camshaft housings and covers are cast aluminum. The camshafts run directly in cylinder head housing covers without bearing inserts.

Camshaft Drive

An inverted tooth chain is used. A mechanical tensioner and two guides control chain motion.

Timing Chain Housing and Cover

The timing chain housing is die cast aluminum and retains the crankshaft front seal.

Intake and Exhaust Manifold

The intake manifold is made of aluminum. The exhaust manifold is cast iron.