Chevrolet Silverado / GMC Sierra. Service manual — part 1895

Fig. 48: Lubrication Description (RPO LH6/LMG/LY5/LC9)
Courtesy of GENERAL MOTORS CORP.

Callout

Component Name

200

Camshaft

205

Camshaft Sprocket

209

Valve Lifter - Non-Active Fuel Management

219

Valve Lifter - Active Fuel Management

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.8L, 5.3L, 6.0L, 6.2L, or 7.0L - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado

Engine lubrication is supplied by a gerotor type oil pump assembly. The oil pump is mounted on
the front of the engine block and driven directly by the crankshaft sprocket. The pump gears
rotate and draw oil from the oil pan sump through a pick-up screen and pipe. The oil is
pressurized as it passes through the pump and is sent through the engine block lower oil gallery.
Contained within the oil pump assembly is a pressure relief valve that maintains oil pressure
within a specified range.

Pressurized oil is directed through the engine block lower oil gallery to the full flow oil filter
where harmful contaminants are removed. A bypass valve is incorporated into the oil filter, which
permits oil flow in the event the filter becomes restricted. A second valve, the active fuel
management oil pressure relief valve is incorporated into the oil pan. The active fuel management
oil pressure relief valve limits oil pressure directed to the upper oil galleries and valve lifter oil
manifold assembly to 379-517 kPa (55-75 psi) maximum. When main oil pressure exceeds 379
kPa (55 psi), the oil pressure relief valve exhausts excess oil to the sump.

Oil is then directed from the filter to the upper main oil galleries and the valve lifter oil manifold
assembly. Oil from the left upper oil gallery is directed to the crankshaft and camshaft bearings.
Oil that has entered both the upper main oil galleries also pressurizes the valve lifter assemblies
and is then pumped through the pushrods to lubricate the valve rocker arms and valve stems. Oil
returning to the pan is directed by the crankshaft oil deflector. The oil pressure sensor is located
at the top rear of the engine.

With active fuel management activated, the engine control module (ECM) commands the 4
solenoids to open, directing oil through the engine block oil galleries to the intake and exhaust
valve lifters for cylinders 1, 4, 6, and 7. Refer to Cylinder Deactivation (Active Fuel
Management) System Description.

LUBRICATION DESCRIPTION (REPO LY6/L92)

407

Oil Pump Screen

413

Oil Pump

437

Oil Filter

451

Valve Lifter Oil Manifold

452

Valve Lifter Oil Filter

455

Active Fuel Management Oil Pressure Relief Valve

706

Oil Pressure Sensor

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.8L, 5.3L, 6.0L, 6.2L, or 7.0L - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado

Fig. 49: Lubrication Description (REPO LY6/L92)
Courtesy of GENERAL MOTORS CORP.

Callout

Component Name

200

Camshaft

209

Valve Lifter - Non-Active Fuel Management

234

Camshaft Position (CMP) Actuator Solenoid Valve

235

CMP Actuator

407

Oil Pump Screen

413

Oil Pump

437

Oil Filter

455

Oil Pressure Relief Valve

555

Valley Cover

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.8L, 5.3L, 6.0L, 6.2L, or 7.0L - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado

Engine lubrication is supplied by a gerotor type oil pump assembly. The oil pump is mounted on
the front of the engine block and driven directly by the crankshaft sprocket. The pump gears
rotate and draw oil from the oil pan sump through a pick-up screen and pipe. The oil is
pressurized as it passes through the pump and is sent through the engine block lower oil gallery.
Contained within the oil pump assembly is a pressure relief valve that maintains oil pressure
within a specified range.

Pressurized oil is directed through the engine block lower oil gallery to the full flow oil filter
where harmful contaminants are removed. A bypass valve is incorporated into the oil filter, which
permits oil flow in the event the filter becomes restricted. A second valve, the oil pressure relief
valve is incorporated into the oil pan. The oil pressure relief valve limits oil pressure directed to
the upper oil galleries to 379-517 kPa (55-75 psi) maximum. When main oil pressure exceeds 379
kPa (55 psi), the oil pressure relief valve exhausts excess oil to the sump.

Oil is then directed from the filter to the upper main oil galleries. Oil from the left upper oil
gallery is directed to the crankshaft and camshaft bearings. Oil that has entered both the upper
main oil galleries also pressurizes the valve lifter assemblies and is then pumped through the
pushrods to lubricate the valve rocker arms and valve stems.

An oil passage at camshaft bearing location 2 permits oil flow into the center of the camshaft. Oil
enters the camshaft exiting at the front and into the camshaft position (CMP) actuator solenoid
valve. The CMP valve spool position is controlled by the engine control module (ECM) and
CMP magnet (752). When commanded by the ECM, the CMP magnet repositions the CMP
actuator solenoid valve spool directing pressurized oil into the CMP actuator to control valve
timing. Refer to Camshaft Actuator System Description .

Oil returning to the pan is directed by the crankshaft oil deflector. The oil pressure sensor is
located at the top rear of the engine.

LUBRICATION DESCRIPTION (RPO L76)

706

Oil Pressure Sensor

752

CMP Magnet

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.8L, 5.3L, 6.0L, 6.2L, or 7.0L - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado