Jaguar XJ-S. Manual - part 11

 
 

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GASKET DRESSINGS:  As noted above, Hylomar is readily available and works just fine.  Hylomar is a blue goo that 
never hardens.  Jaguar mistakenly specified Hylomar for use as a sealant in gasketless joints, which is a large part of 
why these cars leak; it eventually gets blown out of such locations. 

On gaskets, Greg Fronczak of Jag Services prefers a Toyota sealant, part number 023500102.  This is a black 
substance. 

Chad Bolles suggests a non-hardening sealer from a GM dealer, part no. 1050026. 

Roger Homer suggests a Caterpillar product.  “I’m not sure of its official name/number but I just go into the local 
Caterpillar dealer and ask for a tin of Cat Red.”  Bolles and Homer recommend these last two products primarily 
because of ease of disassembly later; the gaskets easily peel off the metal parts with no need for scraping. 

 

SEALANTS:  As noted above, Loctite 518 is readily available and works just fine.  Everything that Loctite makes with 
a number starting with 5 is a sealant, though, and many of them will work in the Jaguar V12.  Loctite 573 and 574 have 
both been used successfully between the tappet blocks and the heads.  Steve Cranswick likes Loctite 5900 Flange 
Sealant.  None of these are likely to be as easy to find as 518, though. 

For those who can’t seem to find Loctite 518, Karl Nelson says, “Permatex is now a division of Loctite, and Permatex 
51813 is the same thing as Loctite 518.  Permatex 51813 is widely available at NAPA stores, and is advertised as 
Anaerobic Flange Sealer.” 

Joe Bialy adds, “The '13' in 51813 signifies the size of the package the 518 comes in.  For instance, IIRC, 51845 is a 
caulking gun sized package of 518.” 

Loctite’s not the only source for sealants.  James Teston points out that Hernon makes similar products, and there’s a 
Loctite/Hernon cross-reference list on the www at 

 

http://www.hernon.thomasregister.com/olc/hernon/cross.htm

 

 

SEALANTS VS. OXYGEN SENSORS:  You should look for an indication that a sealant is “oxygen sensor safe” 
before using it anywhere on an engine fitted with oxygen sensors.  Apparently some sealants will emit something that 
gets in the oil and eventually into the exhaust and ruins the oxygen sensors.  Joe Bialy provides a www site that 
explains all about oxygen sensors, including contamination problems: 

 

http://www.autotruck.net/ms/archives/1999/0999/999hego.asp

 

 

LEAKY GASKETS:  One of the improvements Ford made to the Jaguar product line after they purchased the company 
was that they “Fordified” the gaskets and seals for the V12.  While all of the old style gaskets look like plain paper of 
various thicknesses, the new gaskets are often “Gortex” (teflon) sandwiched around metal foil.  This upgrade is 
explained in Technical Service Bulletin #12-35 dated 8/92, which states that engines were fitted with these gaskets 
from the factory starting with engine #8S86317SA.  All of the upgraded gaskets fit the older engines, so whenever 
engine work is being done it would be wise to use the newer gaskets. 

Redesigned gaskets, along with the new part numbers: 

  

Old 

P/N New 

P/N 

 

Oil Filter Housing 

EAC6337 

EBC 9624 

 

Oil Pan Gasket 

EAC7251, GEG560 

EBC 9623 

 

Cam Cover Gasket, Right 

C29428, TJM536 

EBC 9628 

 

Cam Cover Gasket, Left 

C29429, TJM537 

EBC 9627 

 

Thermostat Housing, Right 

EAC7048, GTG130 

EBC 8330 

 

Thermostat Housing, Left 

EAC7047, GTG129 

EBC 8331 

 

Water Pump Gaskets 

C29626, C36542 

EBC 9629, EBC 9630 

 

Water Pump Elbow 

C36020 

EBC 9636 

 
 

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Valley Cover 

C29485 

EBC 9631 

 

Sandwich Plate Gasket 

EAC7252 

EBC 9637 

 

Coolant Manifold Gaskets 

C30344 

EBC 9634 

 

Exhaust Manifold Gaskets 

C33921, GEG688 

EBC 10199 

 

Throttle Body Gaskets 

C33280 

EBC 9635 

There are more, I just don’t have all the part numbers. 

The original valley cover gasket was a piece of thin paper, and the new one is a piece of thin Gortex -- black on one 
side, red on the other.  This one isn’t sandwiched around metal foil; it’s really flexible, it even comes all crumpled up in 
a bag.  Offhand it wouldn’t appear to make any difference which way is up, but the TSB specifies that it should be 
installed with the black side towards the block.  If you install the valley cover while the heads are off, trim the edges of 
this gasket wherever they protrude out from under the cover to make sure they don’t interfere with head gasket seating. 

Richard Francis indicates the gasket between the water pump and the timing chain cover is also rubbery, no metal.  He 
also says the water pump elbow gasket “was not Gortex; it was black/red material again, though not paper, not metal, 
and really not that rubbery either.”  The TSB says that the water pump elbow gasket should be installed with the black 
side towards the block. 

The TSB clarifies that all of the Gortex and Gortex sandwich gaskets should be assembled dry; no dressing should be 
used.  It also specifies replacement bolts; “Revised bolts have flanged heads to prevent loosening.  Do not use a washer 
on revised (flanged) bolts.”  The TSB only mentions replacement bolts for the oil sump, sandwich plate, and cam 
covers.  See the cam cover sealing discussion starting on page 59 for more ideas on this bolt replacement.  Also see the 
discussion on sandwich plate bolt sealing on page 47. 

This author ordered a set of thermostat housing gaskets by the above part numbers, and received paper gaskets.  They 
are black paper and kinda thin, while the older style is thicker red paper.  The only other difference I can see is that the 
outside edge of the newer 3-bolt cover gasket lacks the bulge at one corner, so it can fit on in any of three orientations.  
I have been told that Gortex sandwich gaskets do exist for the thermostat covers, but part numbers are unknown. 

The original coolant manifold gaskets were apparently very thin paper and later versions were really thick pink 
cardboard; the EBC 9634 gaskets are Gortex/metal sandwiches, and are pretty thin.  There are 12 used on the engine, 
although because some are used under the coolant headers and others are used under blank-off plates they may be listed 
in catalogs as 8 needed in one place and 4 in another.  Note that the steel blank-off plates tend to distort with stress and 
time, especially if they’ve been holding down the thick paper gaskets; prior to reinstalling, it’d be a good idea to run a 
flat file across the bottom to make the surface flat again. 

A single design gasket is used on both sides of the throttle body, between the air filter housing and the throttle body and 
between the throttle body and the intake manifold, so you need a total of four.  The EBC 9635 gasket is a Gortex/metal 
sandwich and has 7 bolt holes in it; four in a rectangular pattern, two more at 10 and 4 o’clock for the hidden bolts that 
hold the throttle body to the intake manifold, and a single loop that can either point straight up or straight down 
depending on which way you flip it.  The TSB says they should be installed with the tab pointing downwards.  The tab 
serves no purpose on the ’83, and can either be cut off or left in place to hang out the edge of the assembled joint. 

Mike Morrin says, “The top gasket set is Jaguar P/N JLM12229, and has all of the new style gaskets.” 

The new gaskets should be widely available.  Be sure to check the part number or description of the gasket as some 
parts people may try to give you the old style to get rid of old stock.  Given the proclivity of the pre-Ford Jaguars to 
leak oil, using the older paper gaskets -- regardless of how cheap you got them -- would be a poor decision. 

Richard Francis ordered a rebuilt water pump in 2006.  “Surprised at getting paper gaskets (plate to block and water 
inlet spout) with my rebuilt water pump from a reputable vendor, I called their president.  He explained that while 
1000's are sold each year, this is first time any customer asked to have the Gortex gaskets packaged with the part.  
Challenging him, he offered to make this recommendation to the outsourced company who actually rebuilds and 
packages the part for the customer.  Wasn't TSB 12-15 issued in 1992? 

“One disadvantage here, which may cause me to return this part, is that it is safe to say that the pump to plate gasket is 
paper as well. 

 
 

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“Of course, if you want the paper gaskets...otherwise put the Gortex in the same order. 

 

INTAKE MANIFOLD GASKETS:  During the Ford gasket upgrade, the 12 individual intake manifold gaskets 
C43354 or AJM687 were replaced with two gaskets; each serves all six ports on one bank.  The part number is NNA-
3020BA.  The original gaskets were either a very hard thick cardboard or an embossed metal piece, and the new 
gaskets are a really thick, soft cardboard. 

If you happen to have a pre-H.E., these new intake manifold gaskets pose a problem.  Peter Smith reports that the 
sections of gasket between the intake ports interfere with installation of the vertical spark plugs used on the pre-H.E..  
He also reports that the 12-piece gaskets are NLA.  If you have a pre-H.E., here’s a plan: set some 5/16” bolts on the 
floor standing on their heads and set one of the new gaskets down over them.  Set the intake manifold over it, using the 
bolts to align the gasket with the manifold.  Use a marker to mark the outline of the manifold onto the gasket.  Then 
take a pair of stout scissors or sheet metal shears and cut that single gasket into six individual gaskets, throwing away 
the sections between intake ports.  Let’s face it, any portion of the gasket that isn’t pinched between the manifold and 
the head is useless, it won’t hurt anything to cut it away. 

The spark plugs on the H.E. are canted inward and are a PITA to install, but the 2-piece gaskets don’t make it any more 
difficult.  Nonetheless, it still might be a nice idea to cut the gaskets into six pieces and discard the useless sections 
between ports; it results in a cleaner appearance in the vee, an area that’s too cluttered already. 

 

EXHAUST MANIFOLD GASKETS:  The original exhaust manifold gaskets are sort of a metal/asbestos/metal 
sandwich with dimpled surfaces, and the newer ones are the same stuff except that they have added a collar around the 
center opening.  This is a significant improvement; the earlier gaskets tend to erode from the exhaust passage outward. 

 

DRY PAPER GASKETS:  For the few places where paper gaskets are still used on the XJ-S, Walt Osborn of Vintage 
Jaguar (page 694) sends this tip:  “When paper gaskets are stored for a certain period of time, they shrink and become 
hard and brittle.  If you are in a hurry, just dip in warm water and pat it dry with a paper towel or shop rag.  Keep doing 
it until it fits.  If you have a little time put it in a plastic bag with a slightly damp rag.  The gasket will usually 
reconstitute overnight.  Once it is okay, remove the rag and seal the bag until ready for use.” 

 

PARTS BOOK CONFUSION:  At the rear end of each intake manifold is an opening covered by a throttle linkage 
support plate and a triangular cover with hose connections for the crossover pipe, all held to the manifold with three 
bolts.  It is plainly obvious that this assembly requires two gaskets, one between the manifold and the throttle linkage 
support plate and one between the throttle linkage support plate and the triangular cover.  The August 1987 Jaguar Parts 
Catalogue shows this assembly on page 1C-15L and 1C-15R, but it shows only one gasket, EAC2650.  It indicates two 
required, but all the other quantities shown on the page are per-car numbers, so one could conclude that it means one 
per manifold.  Worse, many other sources, such as the catalogs from the mail order outfits, base their listings on this 
parts catalog and repeat this error.  Ignore all this misinformation and order two EAC2650 gaskets per side, four total. 

 

LEAKY SEALING WASHERS:  Copper sealing washers work just fine -- once.  The work-hardening properties of 
copper are rather extreme; when fully annealed pure copper is very soft indeed, but just bend or deform it a little bit and 
it gets very hard very suddenly.  Copper sealing washers are intended to exploit this very feature; as the components are 
tightened down on them, they initially crush to form a good seal and then promptly get hard.  If you try to reuse one, 
you almost might as well use a steel washer for sealing. 

Craig Sawyers points out you can reuse copper washers if you anneal them.  “Heat it up to cherry red in a flame (just a 
plumbing gas burner will do, or even the stove) and let it cool slowly.  It will then be as soft as putty, and will tighten 
nicely without too much torque to give a good seal.”  Hanging the washers with little pieces of wire makes it easy to use 
a torch on them.  Believe it or not, a butane cigarette lighter will work -- but you’ll need to hold it on the washer a 

 
 

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while, so it’s best to have one of those long charcoal grille lighters that won’t burn your thumb.  Obviously, if the 
copper washers are boogered up, it’d be a good idea to file them flat before use. 

Is it important to let it cool slowly?  Nope!  In fact, it’s better to dunk it in water.  Martin Lappin says, “Unlike steel, the 
copper will also stay soft if you quench it in cold water.  The advantage of this is it removes the oxide scale from the 
surface.”  You simply cannot quench copper fast enough to cause it to harden, at least not without special equipment; 
dunking it in water isn’t fast enough.  If you don’t dunk it, you’ll have to sand the washer lightly after it cools to get the 
oxide off. 

So why am I wasting space in this book to tell you how to save a few cents by reusing copper washers?  Because you 
need to start annealing new washers.  Sawyers:  “They are supplied as stamped from sheet copper.  In other words they 
are in half-hard anneal.  I always heat treat new washers to put them in a state of soft anneal.  Try it and you'll see what 
I mean.” 

By annealing each time, you can apparently reuse copper seals as many times as you like.  People who use copper head 
gaskets in competition find this a very appealing prospect.  For a ten cent washer, though, you’ll probably want to 
replace them nearly every time anyway just because they eventually get pretty mangled. 

XK’s Unlimited (page 694) offers something called a Stat-O-Seal washer.  It’s an alloy washer with a rubber ring 
around the ID.  They come in 1/8” increments.  Michael Neal says, “The drain plug washer for the S3 XJ6 and XJ-S 
can be replaced with the transmission cooler line banjo bolt seal from an XJ40, EBC4896.  This is a neoprene-lined 
washer that is reusable.”  You don’t really have to seek out Jaguar parts sources, though; these type sealing washers are 
now commonly available in auto parts stores. 

You can also assemble your own homemade equivalent with an O-ring and a flat washer.  For example, to seal a 1/2 
fitting you could slide on a 1/16” thick O-ring with a 1/2” ID and a flat washer with a 5/8” ID so it fits around the O-
ring.  Ideally, the flat washer should be just a bit thinner than 1/16”.  When you tighten down the fitting, first it contacts 
the O-ring and starts to compress it but then sits hard on the flat washer preventing you from overcompressing the O-
ring.  The O-ring ends up fully trapped within the flat washer so it can’t blow out regardless of pressure.  Such 
assemblies provide a reliable seal, and you can easily gather the parts to assemble one to fit any application.  You can 
even put together really tiny versions if needed.  And for optimum durability, you can opt for Viton O-rings (see 
below). 

For the specific application of an oil drain plug, auto parts stores now offer a plug that has a built-in rubber seal under 
the head.  It looks like a stubby washer-faced bolt, except the washer face is made of rubber.  Obviously, if the rubber 
gets chewed up, you need to replace the entire plug. 

The rubber-lined washer, the O-ring and flat washer, and the rubber-sealed drain bolt are all excellent sealing methods 
as long as the application doesn’t get too hot for the rubber.  The rubber will also deteriorate in a decade or so.  Where 
things get hot or you need it to seal longer than a decade, the copper washer is the way to go.  Now, let’s move on to 
bad ideas: 

If you find any aluminum sealing washers, throw them away.  They cannot be reused.  In fact, they’re not all that great 
the first time. 

Fiber washers  work fine once or twice as long as you don’t overtighten them, but eventually they tend to split open -- 
and not necessarily while you’re tightening them; they may crack open later when you’re 100 miles from home.  They 
are also generally unsuitable for high-pressure applications, although some fittings address this by enclosing the fiber 
washer within a recess to prevent it from blowing out. 

Auto parts stores offer plastic sealing washers; sometimes they are packaged with a replacement oil drain plug.  
Sometimes they have circular ribs on them, apparently to improve sealing.  Sometimes they have a little flag hanging 
off one side, apparently to stick out the side of the joint and tell you there’s a plastic sealing washer in there.  These 
things work for low-pressure applications such as an oil drain plug, but don’t use them on any line that holds pressure.  
You must be careful while installing; you can overtighten them and squeeze them right out of the joint, especially if 
there’s a little oil involved.  In general, you’d be well advised to just throw them away.