Skylark L4-138 2.3L DOHC VIN D MFI QUAD 4 (1989)
Cylinder Head Gasket: All Technical Service Bulletins
Service Procedure (Revised)
1.
Completely drain the cooling system.
IMPORTANT:
The cylinder block, head, radiator and heater core must be completely drained of coolant since the old coolant will be contaminated with
combustion residue. Refer to the appropriate section of your service manual for draining procedure.
2.
Remove the cylinder head. Refer to the appropriate service manual section.
3.
Inspect the timing chain tensioner shoe, refer to Figure 1.
IMPORTANT:
On 1988 and earlier vehicles, also check the thickness of the backing plate. If the thickness is 2 mm (0.079 in.), replace the tensioner shoe and stud
with GM Kit Part No. 12340864. The new tensioner shoe backing plate will be 3.7 mm (0.146 in.) thick, refer to Figure 1. GM P/N 24570357 will
be an updated chain with smooth edges that will reduce tensioner shoe wear.
4.
If the tensioner shoe is broken and the chain is worn from contacting the medal surface, use GM kit P/N 12340864 to replace the tensioner shoe
and stud. P/N 24570357 to replace the chain and P/N 24570356 to replace the tensioner.
