XJ-6 L6-3.6L (1989)
Cylinder Head Gasket: Technical Service Bulletins
Cylinder Head Casting, Gasket - Revised
12-48
Cylinder Head - Erosion of Head Gasket
Surface - Use Filler Material
MODEL: AJ6 Engine
DATE: 6/94
Supersedes: Technical Bulletin 12-46
Issue:
Erosion can occur on the cylinder head gasket mating surface around the cylinder head coolant passages.
To prevent erosion around the coolant passages, the cylinder head casting and head gasket have been revised beginning with the following VIN's:
4.0L Sedan: VIN 677386
4.0L XJS: VIN 187554
Repair Policy:
Cylinder heads must NOT be removed to inspect for erosion. Inspection is necessary only when the cylinder head is removed for other repair work.
Action:
When a cylinder head is removed, inspect the head gasket surface for erosion and perform the following procedures:
Inspection Procedure:
Clean the gasket mating surface using a soft wire brush or a fine abrasive pad and solvent.
Place a new head gasket on the cylinder head as a template, refer to Fig. 1.
If the erosion extends to the combustion chamber fire ring (Fig. 1A & C), the cylinder head must be resurfaced to the following specifications:
Minimum thickness between top and bottom face:
3.6L engines = 5.101" (129.57 mm)
4.OL engines = 5.108" (129.76 mm)
Minimum parallelism between faces = .002" (.05 MM).
Surface finish: to exceed 1.6 microns.
Repair Procedure:
