Cutlass L4-138 2.3L VIN A FI HP (1990)
9.
Clean each head bolt seat boss on the cylinder head. Clean the bolt holes in the cylinder block, refer to Figure 4. MAKE SURE THAT ALL
PUDDLES OF OIL AND COOLANT HAVE BEEN REMOVED FROM BOLT HOLES OTHERWISE THE TIGHTENING SEQUENCE WILL
NOT OBTAIN THE PROPER CLAMP LOAD BECAUSE OF HYDRA-STATIC LOCK. IF THE BOLT HOLES ARE NOT CLEANED THE
HEAD GASKET MAY LEAK.
10.
Replace the oil flow check valve (see Figure 5) in 1987 through 1989 model year vehicles. Refer to the applicable 1991 model year service
manual. The check valve does not need to be replaced in 1990 or newer vehicles or those vehicles where the check valve has been previously
replaced.
IMPORTANT:
To determine if the check valve has been previously replaced on 1987 through 1989 vehicles, 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 valve and should not be replaced (Figure 5).
11.
Apply clean engine oil SPARINGLY to the threads and the bottom side of the flange of the bolt (Figure 6).
NOTICE:
The following tightening procedure must be used to assure gasket life. Failure to follow this procedure exactly may result in cylinder head gasket
leakage.
