Cylinder Head Oil Leak or Weepage Found on Some 4.6L and 5.4L Engines - Engine Builder Magazine
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Cylinder Head Oil Leak or Weepage Found on Some 4.6L and 5.4L Engines


Oil weepage is not considered detrimental to this engine’s
performance or durability. An oil leak may be caused by metal chip
debris lodged between the head gasket and the block, chip debris
between the cylinder head and the head gasket, or by damage to the
cylinder head sealing surface that occurred during the manufacturing

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Once an oil leak is verified with a black light test at
the head gasket joint, replacement of the head gasket can be performed.
If the head was damaged by chip contamination, the head should be
replaced. A revised “service-only” gasket is now released for both of
these cases.

Required for service are:

A straightedge (machine flatness toleranced to 0.0002” per foot in
length) that’s available from local tool dealers or as provided by Ford
Motor Company;


• Motorcraft Silicone Gasket Remover (ZC-30);

• Metal Surface Prep (ZC-31); and

• Service-only gasket (3U7Z-6051-BA for driver’s side and/or 3U7Z-6051-AA for passenger’s side) with the new embossed area.

Repair Procedure

heads damaged by brinnelling (depression marks from original gasket) of
the head may still be reusable. The revised “service-only” gasket has a
feature by which the embossed sealing area does not follow the same
sealing path as the original gasket. This area is surrounding the High
Pressure Oil Feed (HPOF) area. It’s triangular in shape and is found in
the rear of the passenger’s side cylinder head, or in the front of the
driver’s side cylinder head (see Figures 1 and 2).


If performing in vehicle service, the engine should be allowed to cool
before removing the head or warpage may occur in deck flatness.

cylinder head and block decks should be cleaned before performing a
flatness check. Dark metal stains below the surface of the metal are
normal. Do not attempt to polish off the stains with grinders or
scrapers. Use a plastic scraper (or plastic ice scraper or equivalent)
to pull away any residual silicone RTV with ZC-30 and ZC-31 applied in

The repair information and labor times have been
updated for both cars and trucks using 4.6L 2V and 5.4L 2V and
Supercharged 5.4L engines. These include instructions to remove the
engine prior to removing the cylinder head. Labor times allow for extra
time in engine removal and cylinder head deck leak repair out of the


Cylinder head kits are available on most applications
from Ford and include complete head assembly, with cam and valves; head
bolts, service-only head gasket; both intake gaskets exhaust gasket;
one rocker cover gasket; and one set of exhaust studs and nuts.

it’s found that only one head is leaking, it’s not necessary to remove
the other head. Repair only the side for which leakage occurs.

Technical Editor Eric Seifert is an ASE-certified Master Technician and
Engine Machinist, with 20 years of independent shop and parts store


Technical service bulletin courtesy of ALLDATA.

For additional information, visit

figure 1Figure 2

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