Visual Inspection

Camshaft Position Actuators

Fig 1: Identifying Front Of Exhaust Camshaft Position Actuators
Courtesy of GENERAL MOTORS CORP.
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 2: Identifying Back Of Exhaust Camshaft Position Actuators
Courtesy of GENERAL MOTORS CORP.
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 3: Identifying Front Of Intake Camshaft Position Actuators
Courtesy of GENERAL MOTORS CORP.
3. Inspect the front of the 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 4: Identifying Back Of Intake Camshaft Position Actuators
Courtesy of GENERAL MOTORS CORP.
4. Inspect the back of the 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)
5. Replace a damaged camshaft position actuator.

Camshaft Position Actuator Oil Control Valves

Fig 5: Identifying Camshaft Position Actuator Oil Control Valves
Courtesy of GENERAL MOTORS CORP.
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 Roller Chain

Fig 6: Identifying Front Of Left Intermediate Sprocket
Courtesy of GENERAL MOTORS CORP.
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 7: Identifying Back Of Left Intermediate Sprocket
Courtesy of GENERAL MOTORS CORP.
2. Inspect the back of the 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.

Left Intermediate Sprocket with Primary (IT) Inverted Tooth Chain

Fig 8: Identifying Front Of Left Intermediate Sprocket
Courtesy of GENERAL MOTORS CORP.
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 9: Identifying Back Of Left Intermediate Sprocket
Courtesy of GENERAL MOTORS CORP.
2. Inspect the back of the 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 Roller Chain

Fig 10: Identifying Front Of Right Intermediate Sprocket
Courtesy of GENERAL MOTORS CORP.
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 bearing 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 11: Identifying Back Of Right Intermediate Sprocket
Courtesy of GENERAL MOTORS CORP.
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.

Right Intermediate Sprocket with Primary (IT) Inverted Tooth Chain

Fig 12: Identifying Front Of Right Intermediate Sprocket
Courtesy of GENERAL MOTORS CORP.
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 bearing 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 13: Identifying Back Of Right Intermediate Sprocket
Courtesy of GENERAL MOTORS CORP.
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 Roller Chain

Fig 14: Identifying Crankshaft Sprocket Inspection Points (Primary Roller Chain)
Courtesy of GENERAL MOTORS CORP.
1. Inspect the crankshaft sprocket for the following:
   • Sprocket damage (1)
   • Bore damage (2)
   • Keyway damage (3)
   • Damage to the cushion material (4)
2. Replace a damaged crankshaft sprocket.

Crankshaft Sprocket with Primary (IT) Inverted Tooth Chain

Fig 15: Identifying Crankshaft Sprocket Inspection Points (Primary Inverted Tooth Chain)
Courtesy of GENERAL MOTORS CORP.
1. Inspect the crankshaft sprocket for the following:
   • Sprocket damage (1)
   • Bore damage (2)
   • Keyway damage (3)
2. Replace a damaged crankshaft sprocket.

Primary and Secondary Timing Chains with Roller Chain

Fig 16: Identifying Primary & Secondary Timing Chain Inspection Points (Roller Chain)
Courtesy of GENERAL MOTORS CORP.
1. Inspect the primary and/or secondary timing chain for the following:
   • Binding or worn rollers (1)
   • Loose links (2)
   • Loose pins (3)
2. Replace a damaged primary and/or secondary timing chain.

Primary Timing Chain with (IT) Inverted Tooth Chain

Fig 17: Identifying Primary Timing Chain (Inverted Tooth Chain)
Courtesy of GENERAL MOTORS CORP.
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 18: Identifying Primary Timing Chain Upper Guide
Courtesy of GENERAL MOTORS CORP.
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 19: Identifying Primary Timing Chain Lower Guide
Courtesy of GENERAL MOTORS CORP.
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)
IMPORTANT: The primary camshaft drive chain lower guide is not a serviceable component. If the primary camshaft drive chain lower guide is to be reused, the primary camshaft drive chain lower guide is not to be removed from the oil pump cover. If the primary camshaft drive chain lower guide must be replaced, the oil pump must be replaced.
2. Replace a damaged primary timing chain lower guide by replacing the oil pump.

Left Secondary Timing Chain Guide

Fig 20: Identifying Left Secondary Timing Chain Guide
Courtesy of GENERAL MOTORS CORP.
1. Inspect the left secondary timing chain guide 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 21: Identifying Right Secondary Timing Chain Guide
Courtesy of GENERAL MOTORS CORP.
1. Inspect the right secondary timing chain guide 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 22: Identifying Front Of Left Secondary Timing Chain Shoe
Courtesy of GENERAL MOTORS CORP.
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 23: Identifying Back Of Left Secondary Timing Chain Shoe
Courtesy of GENERAL MOTORS CORP.
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 24: Identifying Front Of Right Secondary Timing Chain Shoe
Courtesy of GENERAL MOTORS CORP.
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 25: Identifying Front Of Right Secondary Timing Chain Shoe
Courtesy of GENERAL MOTORS CORP.
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 26: Identifying Primary Timing Chain Tensioner
Courtesy of GENERAL MOTORS CORP.
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 Primary Camshaft Drive Chain Tensioner Installation .
3. Replace a damaged primary timing chain tensioner.

Left Secondary Timing Chain Tensioner

Fig 27: Identifying Left Secondary Timing Chain Tensioner
Courtesy of GENERAL MOTORS CORP.
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 Secondary Camshaft Drive Chain Tensioner Installation - Left .
3. Replace a damaged left secondary timing chain tensioner.

Right Secondary Timing Chain Tensioner

Fig 28: Identifying Right Secondary Timing Chain Tensioner
Courtesy of GENERAL MOTORS CORP.
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 Secondary Camshaft Drive Chain Tensioner Installation - Right .
3. Replace a damaged right secondary timing chain tensioner.