Additional Recommended Inspections

Figure 1. Timing Chain Tensioner Shoe:

INSPECT THE TIMING CHAIN TENSIONER SHOE
- Remove the cylinder head.


- Inspect the timing chain tensioner shoe. If the tensioner shoe has grooves worn into it in excess of 1.14 mm (0.045 in.) from the chain, replace the tensioner shoe and stud with GM Part No. 12340864.

Oil Flow Check Valve:

INSPECT THE OIL FLOW CHECK VALVE
- The oil flow check valve is located in the cylinder block on the timing chain side of the engine. (Look into the oil transfer port located under the head gasket).

- Replace the oil flow check valve if it has not been previously replaced.

To determine if the check valve has been previously shine a flashlight into the oil check valve. If there are three dimples immediately above the check ball, it is the new style oil flow check valve and should not be replaced.