Chevrolet Silverado / GMC Sierra. Service manual — part 2135

5. If the pintle of the CMP magnet is binding or does not move within the proper range of

travel, replace the CMP magnet as an assembly.

CAMSHAFT POSITION ACTUATOR SOLENOID VALVE INSPECTION (ON-VEHICLE)

Fig. 81: View Of Proper Valve Spool Position
Courtesy of GENERAL MOTORS CORP.

IMPORTANT: Do not use the camshaft position (CMP) actuator solenoid

valve again. Install a NEW valve during assembly. The
inspection procedure below is provided for on-vehicle
diagnostic purposes only.

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

1. With the CMP magnet removed, inspect for a sticking valve spool or broken valve spool

spring.

2. Depress the valve spool into the housing. The valve should move freely with no binding or

sticking and minimal resistance inward. When released, the valve spring should return the
spool to the proper extended position (1) of 6.08-6.12 mm (0.239-0.241 in).

CAMSHAFT POSITION ACTUATOR SOLENOID VALVE INSPECTION (OFF-VEHICLE)

Fig. 82: View Of CMP Inspection Points
Courtesy of GENERAL MOTORS CORP.

IMPORTANT: Do not use the camshaft position (CMP) actuator solenoid

valve again. Install a NEW valve during assembly. The
inspection procedure below is provided for off-vehicle

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

1. Inspect the CMP valve for the following conditions:

Dirt, debris, or restrictions within the oil passages (1)

Damaged threads (2)

If the threads of the valve are damaged, also inspect the threads in the front of the
camshaft for damage.

Dirt, debris, or restrictions within the oil inlet check valve (3)

If debris is detected, the engine assembly should be inspected to determine the source
of contamination.

diagnostic purposes only.

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. 83: View Of Proper Valve Spool Position
Courtesy of GENERAL MOTORS CORP.

2. Inspect for a sticking valve spool or broken valve spool spring.

3. Depress the valve spool into the housing. The valve should move freely with no binding or

sticking and minimal resistance inward. When released, the valve spring should return the
spool to the proper extended position (1) of 6.08-6.12 mm (0.239-0.241 in).

VALVE ROCKER ARM AND PUSH ROD CLEANING AND INSPECTION

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