Visual Inspection

Camshaft Thrust Washers (If Equipped)

Fig 1: Camshaft Thrust Washer
Courtesy of GENERAL MOTORS COMPANY
1. Inspect the camshaft thrust washers for deep scoring or uneven wear (1).
2. Replace as necessary.

Camshaft Position Actuators

Fig 2: Front Of Exhaust Camshaft Position Actuators Inspection Locations
Courtesy of GENERAL MOTORS COMPANY
NOTE:

Actual camshaft position actuators may vary in appearance from the ones shown.

1. Inspect the front of the exhaust camshaft position actuators for the following:
   • Sprocket damage (1)
   • Reluctor/sensor wheel damage (2)
   • Camshaft position actuator bolt seating/sealing inner hub flange damage (3)
Fig 3: Back Of Exhaust Camshaft Position Actuators Inspection Locations
Courtesy of GENERAL MOTORS COMPANY
2. Inspect the back of the exhaust camshaft position actuators for the following:
   • Sprocket damage (1)
   • Camshaft locating pin damage (2)
   • Camshaft seating/sealing inner hub flange damage (3)
   • Blockage to the oil passages (4)
   • Loose or missing housing bolts (5)
Fig 4: Front Of Intake Camshaft Position Actuators Inspection Locations
Courtesy of GENERAL MOTORS COMPANY
3. Inspect the front of the left intake camshaft position actuators for the following:
   • Sprocket damage (1)
   • Reluctor/sensor wheel damage (2)
   • Camshaft position actuator oil control valve bolt seating/sealing inner hub flange damage (3)
Fig 5: Back Of Intake Camshaft Position Actuators Inspection Locations
Courtesy of GENERAL MOTORS COMPANY
4. Inspect the back of the left intake camshaft position actuators for the following:
   • Sprocket damage (1)
   • Camshaft locating pin damage (2)
   • Camshaft seating/sealing inner hub flange damage (3)
   • Blockage to the oil passages (4)
   • Loose or missing housing bolts (5)
Fig 6: Front Of Intake Camshaft Position Actuators Inspection Locations
Courtesy of GENERAL MOTORS COMPANY
5. Inspect the front of the right intake camshaft position actuators for the following:
   • Sprocket damage (1)
   • Reluctor/sensor wheel damage (2)
   • Camshaft position actuator oil control valve bolt seating/sealing inner hub flange damage (3)
Fig 7: Back Of Intake Camshaft Position Actuators Inspection Locations
Courtesy of GENERAL MOTORS COMPANY
6. Inspect the back of the right intake camshaft position actuators for the following:
   • Sprocket damage (1)
   • Camshaft locating pin damage (2)
   • Camshaft seating/sealing inner hub flange damage (3)
   • Blockage to the oil passages (4)
   • Loose or missing housing bolts (5)
7. Replace a damaged camshaft position actuator.

Camshaft Position Actuator Oil Control Valves

Fig 8: Camshaft Position Actuator Oil Control Valves Inspection Areas
Courtesy of GENERAL MOTORS COMPANY
1. Inspect the camshaft position actuator oil control valves for the following:
   • Blockage to the oil passage (1)
   • Missing or damaged oil screen clip (2)
   • Blockage or damage to the oil screen (3)
   • Damage to the sealing surface for the camshaft position actuator oil control valve solenoid oil seal (4)
   • Damage to the bracket (5)
   • Damage to the wiring harness connection and/or terminals (6)
2. Replace a damaged camshaft position actuator oil control valve.

Left Intermediate Sprocket with Primary and Secondary Inverted Tooth (IT) Chain

Fig 9: Front Of Left Intermediate Sprocket Inspection Locations
Courtesy of GENERAL MOTORS COMPANY
1. Inspect the front of the left intermediate sprocket for the following:
   • Damage to the primary camshaft drive chain sprocket (1)
   • Damage to the hub bearing (2)-Ensure the hub bearing spins freely. If the hub bearing wobbles, is noisy, or feels rough when rotated, replace the intermediate sprocket.
   • Damage to the bolt flange seating/sealing surface (3)
Fig 10: Back Of Left Intermediate Sprocket Inspection Locations
Courtesy of GENERAL MOTORS COMPANY
2. Inspect the back of the left intermediate sprocket for the following:
   • Damage to the left secondary camshaft drive chain sprocket (1)
   • Damage to the bearing hub-to-engine block sealing surface (2)
3. Replace a damaged left intermediate sprocket.

Right Intermediate Sprocket with Primary and Secondary Inverted Tooth (IT) Chain

Fig 11: Front Of Right Intermediate Sprocket Inspection Locations
Courtesy of GENERAL MOTORS COMPANY
1. Inspect the front of the right intermediate sprocket for the following:
   • Damage to the right secondary camshaft drive chain sprocket (1)
   • Damage to the hub bearing (2)-Ensure the hub bearing spins freely. If the hub bearing wobbles, is noisy, or feels rough when rotated, replace the intermediate sprocket.
   • Damage to the bolt flange seating/sealing surface (3)
Fig 12: Back Of Right Intermediate Sprocket Inspection Locations
Courtesy of GENERAL MOTORS COMPANY
2. Inspect the back of the right intermediate sprocket for the following:
   • Damage to the primary camshaft drive chain sprocket (1)
   • Damage to the bearing hub-to-engine block sealing surface (2)
3. Replace a damaged right intermediate sprocket.

Crankshaft Sprocket with Primary Inverted Tooth (IT) Chain

Fig 13: Crankshaft Sprocket Inspection Locations
Courtesy of GENERAL MOTORS COMPANY
1. Inspect the crankshaft sprocket for the following:
   • Sprocket damage (1)
   • Bore damage (2)
   • Keyway damage (3)
2. Replace a damaged crankshaft sprocket.

Secondary Timing Chains with Inverted Tooth (IT) Chain

Fig 14: Primary And Secondary Timing Chain Inspection Locations
Courtesy of GENERAL MOTORS COMPANY
1. Inspect the secondary timing chain for the following:
   • Binding or worn links (1)
   • Loose links (2)
   • Loose pins (3)
2. Replace a damaged secondary timing chain.

Primary Timing Chain with Inverted Tooth (IT) Chain

Fig 15: Primary And Secondary Timing Chain Inspection Locations
Courtesy of GENERAL MOTORS COMPANY
1. Inspect the primary timing chain for the following:
   • Binding or worn links (1)
   • Loose links (2)
   • Loose pins (3)
2. Replace a damaged primary timing chain.

Primary Timing Chain Upper Guide

Fig 16: Primary Timing Chain Upper Guide Inspection Locations
Courtesy of GENERAL MOTORS COMPANY
1. Inspect the primary timing chain upper guide for the following:
   • Worn guide surface (1)
   • Cracked or broken guide surface (2)
   • Cracked or damaged guide base (3)
2. Replace a damaged primary timing chain upper guide.

Primary Timing Chain Lower Guide

Fig 17: Primary Timing Chain Lower Guide Inspection Locations
Courtesy of GENERAL MOTORS COMPANY
1. Inspect the primary timing chain lower guide for the following:
   • Worn guide surface (1)
   • Cracked or broken guide surface (2)
   • Cracked or damaged guide base (3)
2. Replace a damaged primary timing chain lower guide.

Left Secondary Timing Chain Guide

Fig 18: Left Secondary Timing Chain Guide Inspection Locations
Courtesy of GENERAL MOTORS COMPANY
1. Inspect the left secondary timing chain guides for the following:
   • Worn guide surface (1)
   • Cracked or broken guide surface (2)
   • Cracked or damaged guide base (3)
2. Replace a damaged left secondary timing chain guide.

Right Secondary Timing Chain Guide

Fig 19: Right Secondary Timing Chain Guide Inspection Locations
Courtesy of GENERAL MOTORS COMPANY
1. Inspect the right secondary timing chain guides for the following:
   • Worn guide surface (1)
   • Cracked or broken guide surface (2)
   • Cracked or damaged guide base (3)
2. Replace a damaged right secondary timing chain guide.

Left Secondary Timing Chain Shoe

Fig 20: Front Of Left Secondary Timing Chain Shoe Inspection Locations
Courtesy of GENERAL MOTORS COMPANY
1. Inspect the front of the left secondary timing chain shoe for the following:
   • Worn shoe surface (1)
   • Cracked or broken shoe surface (2)
   • Cracked or damaged shoe (3)
Fig 21: Left Secondary Timing Chain Tensioner Contact Pad
Courtesy of GENERAL MOTORS COMPANY
2. Inspect the back of the left secondary timing chain shoe for a damaged, worn, or missing left secondary timing chain tensioner contact pad (1).
3. Replace a damaged left secondary timing chain shoe.

Right Secondary Timing Chain Shoe

Fig 22: Front Of Right Secondary Timing Chain Shoe Inspection Locations
Courtesy of GENERAL MOTORS COMPANY
1. Inspect the front of the right secondary timing chain shoe for the following:
   • Worn shoe surface (1)
   • Cracked or broken shoe surface (2)
   • Cracked or damaged shoe (3)
Fig 23: Right Secondary Timing Chain Tensioner Contact Pad
Courtesy of GENERAL MOTORS COMPANY
2. Inspect the back of the right secondary timing chain shoe for a damaged, worn, or missing right secondary timing chain tensioner contact pad (1).
3. Replace a damaged right secondary timing chain shoe.

Primary Timing Chain Tensioner

Fig 24: Primary Timing Chain Tensioner Inspection Locations
Courtesy of GENERAL MOTORS COMPANY
1. Inspect the primary timing chain tensioner for worn primary timing chain tensioner shoe surface (1).
2. Inspect the primary timing chain tensioner for locked or binding timing chain tensioner. Reset the plunger (3) and ensure the plunger moves freely (2) in and out of the body of the tensioner. Refer to Camshaft Timing Chain Components Installation .
3. Replace a damaged primary timing chain tensioner.

Left Secondary Timing Chain Tensioner

Fig 25: Left Secondary Timing Chain Tensioner Inspection Locations
Courtesy of GENERAL MOTORS COMPANY
1. Inspect the left secondary timing chain tensioner for damaged plunger-to-shoe contact surface (1).
2. Inspect the left secondary timing chain tensioner for locked or binding timing chain tensioner. Reset the plunger (3) and ensure the plunger moves freely (2) in and out of the body of the tensioner. Refer to Camshaft Timing Chain Components Installation .
3. Replace a damaged left secondary timing chain tensioner.

Right Secondary Timing Chain Tensioner

Fig 26: Right Secondary Timing Chain Tensioner Inspection Locations
Courtesy of GENERAL MOTORS COMPANY
1. Inspect the right secondary timing chain tensioner for damaged plunger-to-shoe contact surface (1).
2. Inspect the right secondary timing chain tensioner for locked or binding timing chain tensioner. Reset the plunger (3) and ensure the plunger moves freely (2) in and out of the body of the tensioner. Refer to Camshaft Timing Chain Components Installation .
3. Replace a damaged right secondary timing chain tensioner.