NUMBER: 67-26
DATE: 2-13-67
GROUP: Engine
SUBGROUP: Miscellaneous

MODELS: All Models Equipped With 1725 Engines
SUBJECT: Engine Oil Leaks

Before any detailed examination of oil leaks is attempted, be sure that:

  1. The oil level is correct and that no overfilling has occurred.
  2. The engine unit is clean, short road test carried out, and exact source of the leak established.

Oil Pan (Steel Press)

  1. Remove the oil pan and check to be sure all mounting flanges are flat especially adjacent to the front and rear round sections. Using a straight edge pressed across each round section, be sure that the gasket surface of the flange is flat right up to the edge where it joins the cut away. If necessary build up the mounting flange with solder until there is a well formed right angled joint.
  2. Check that the oil pump bolt holes are tapped completely into the cylinder block.
  3. Fit new gaskets and bearing cap seals being sure that the seals are fitted after the gaskets so that they overlap the gasket. Lightly coat the ends of the seals with gasket compound to be sure and adequate seal is made between the bearing cap seal and gasket.


NOTE: Although seals and gaskets may appear slightly too long on fitting, no attempt must be made to shorten them as this may well lead to subsequent oil leaks.

Timing Cover Area

1. Engine mounting plate to cylinder block.
Where leaks occur in this area, it is recommended that the engine mounting plate is removed, examined for distortion and replaced where necessary. Before re-fitting, check alignment of the front main bearing cap with the font face of the cylinder block. Where necessary loosen the front main bearing cap and re-tighten so that the front face is flush with the cylinder block using a straight edge across both faces.

3. Timing chain lubrication pipe.
Check to be sure that the pipe is not damaged as this may result in flooding of the timing cover. Whenever it is found necessary to remove and re-fit pipe, be sure that the ball and spring are correctly positioned.

4. Timing Cover.
If the timing cover cannot be correctly centralized, the run out of the pulley or crankshaft should be checked using a dial indicator mounted on the timing cover.

5. Timing Cover Base Nut.
A leak can emanate along the threads of the base stud and this may be incorrectly diagnosed as a timing pulley leak. It is recommended that the threads of the stud and faces of the fibre washer are coated with gasket compound before fitting.

Tappet Cover

Remove and check for distortion and replace if damaged or where excessive distortion is present. On engines with aluminum heads be sure that there is no excessive protrusion of the tappet cover gasket. Where necessary trim head gasket corners flush with the cylinder head and block. Re-fit tappet cover with new gasket using gasket compound. Do not over-tighten bolts, otherwise distortion of the cover may occur.

Rocker Cover

Be sure on replacement of the rocker cover gasket that it is held correctly in position by the cover flanges and that on tightening it is not allowed to bow. It is recommended that the gasket is fitted to the cover using gasket compound before fitting of the assembly to the cylinder head.

Distributor Base

A thin paper gasket should be made up to fit between the distributor base and the cylinder block using a thin application of gasket compound.

T.H. Bullard
Manager — Service & Parts

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