Cylinder Head Casting, Gasket - Revised
12-48Cylinder 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:
If erosion is confined to the non-critical area surrounding the coolant passage (Fig. 1 D), repair the cylinder head face to its original profile using locally obtained epoxy plastic filler material, such as:
^ Loctite Weld
^ J-B Weld
^ Marine Tex
Finish the filler material with a hand file so that it is flush with the original cylinder head surface. Clear any filler material from the coolant passages and bolt holes.
CAUTION:
Do not score or damage the original cylinder head surface.
NOTE:
Upon reassembly, use only phosphate free antifreeze/corrosion inhibitor (JAG 111) in the cooling system in a 50% concentration (specific gravity 1.079).
Warranty Policy:
Cylinder heads replaced on warranty must be returned to Jaguar Cars for inspection.
If a returned cylinder head is found to be in repairable condition (using criteria provided in this bulletin), the claim will be debited for the cylinder head cost, less the cost to repair the original head.
Warranty Information:
Use fault code and repair operation number for the problem initiating cylinder head removal, adding the following repair operation and time:
Description R.O. Number Time Allowance
Fill and finish cylinder head 12.91.16 0.75 hrs.
mating face erosion (cylinder
head removed)
If the cylinder head required resurfacing according to the guidelines given in the Inspection Procedure, use normal procedures to claim sublet time as detailed in section E and F of the Jaguar Cars Warranty Manual.
Parts Information
Part Number Description
EBC 10256 Head Gasket
JLM 11088 Head Gasket Kit
There is a parts allowance of $7.00 for locally obtained epoxy plastic filler material.