Timing Chain Sprockets, Guides, And TENSIONER Inspection (DOHC)

Check the timing sprocket for wear, damage, and cracks.

1. Inspect the chain for wear and damaged links.
2. Inspect the chain guides for wear and cracks.

   Chain Track Wear 

   Standard: 0.0 mm 

   Service Limit: 1.0 mm (0.0394 in.) 

   Fig 1: Timing Chain Components

   Courtesy of GENERAL MOTORS CORP.
3. Inspect timing sprocket teeth on the camshaft gears, the crankshaft gear, and or the key for wear.
   Fig 2: Inspecting Timing Sprocket Teeth And Crankshaft Gear

   Courtesy of GENERAL MOTORS CORP.
4. Inspect the tensioner for operation:
   1. Release the plunger lock and make sure the piston moves freely.
   2. Make sure the oil feed hole is open and not plugged. Submerge the tensioner in oil or solvent. Depress the plunger and observe fluid flow from the tensioner body. Inspect the cylinder block port for blockage.
   3. Measure plunger travel (chain and guides installed).

      Plunger Travel 

      Standard: 1.16-9.85 mm (0.045-0.388 in.) 

      Service Limit: 18.0 mm (0.7092 in.) max. 

      Fig 3: Measure Plunger Travel

      Courtesy of GENERAL MOTORS CORP.