in a Book
STRATEGIES: For those obsessed with keeping their cars
in original condition, obviously only original parts will
do. The suggestions below and throughout this book are for
those who simply want their cars to run, and to minimize
cost and grief in the process.
Experienced British car enthusiasts will agree that most
of their reliability problems come from two sources:
Non-metallic parts and Lucas electrics. This is especially
true for Jaguars, where the rest of the car is generally
Rumors abound as to why the rubber and plastic parts on
British cars tend to crap out so soon. One rumor says there
is a law in Britain requiring the use of natural rubber
rather than the far superior synthetic elastomers. Whatever
the cause, the Jaguar owner is well advised to replace the
original Jaguar seals, hoses, belts, etc., with non-British
substitutes whenever feasible. The same replacement strategy
applies for other non-metallic parts.
It has been suggested that the various vinyl and rubber
protectants on the market, such as STP Son Of A Gun, can be
used to help many rubber components last longer. Sandy
Gibbs: "When I owned a TR8 I had many of the same problems
regarding engine heat and rubber components. I found Armor
All and Son of a Gun were useless unless applied every three
or four days (if you drive the car much). What did work was
brake fluid, of all things. You have to soak the part in
question pretty well then rub the fluid in. Let the part dry
before running the car. This procedure may have to be
repeated two or three days in a row but then the rubber is
revitalized, after that one need only repeat the procedure
every two or three months. The key here is keeping the brake
fluid off anything but the rubber part. This process works
on nearly any rubber part except, for some reason,
Lucas has been called the "Father of Darkness". Contrary
to popular opinion, Lucas did not invent darkness -- they
merely perfected it to a fine art! The owner is well advised
to replace Lucas electrical components with alternative
products when feasible. It should be noted that many of the
electrical parts on a Jag are not really Lucas; the "Jaguar"
stereo is probably made in Japan, and the EFI components are
Other than electrical and non-metallic parts, Jaguar
components are typically excellent, and most are reasonably
priced. Whether it is better to replace a broken item with
the Jaguar original or a substitute must be decided on an
individual basis. A good general rule is: if the original
failed of its own accord, it might be better to try another
source. But if the failure was secondary (due to something
else failing first), the Jaguar parts may very well be the
best there are; substitutions are in order only where the
prices of the originals are excessive.
Regarding rebuilt parts, Randy Wilson says, "There are
many companies out there that rebuild to a price, replacing
only the "common" failure part. Their attitude is it's
cheaper to only replace the one part and let the consumer
figure out which units need more work than it is to full
rebuild and test every unit. This is true with electrical,
a/c, steering gear, and other things. The real sad part is
these unscrupulous clowns often drive the reputable
rebuilders out of the market by the price difference.
"I bring this up because I've seen several instances of
this... alternators and steering racks. Rebuilds are a pain.
The cheap ones are no bargain. And just buying an expensive
one is no guarantee. It may be a thorough rebuild, or it may
be a cheap one that your vendor is making a killing on. The
only recommendations I can make that are available to the
general public (US)...For electrical, units rebuilt by Bosch
are good. The ones by Lucas used to be the best
going... but Lucas gave up competing with the cheapies...
and joined them by selling off their name."
MANUALS: For a listing of sources
for manuals, see "PUBLICATIONS AND PERIODICALS."
As mentioned elsewhere, this book is not intended
to substitute for a proper repair manual; you will need to
buy one. In general, there appear to be three to choose
from: a "Repair Operation Manual" from Jaguar intended for
owners, a set of shop manuals from Jaguar intended for
dealers and authorized mechanics, and a Haynes manual. The
Jaguar publications come in several varieties for different
model years, while the Haynes appears to have been published
in only one version.
The Repair Operation Manual, part no. AKM 3455 (along
with a Supplement, part no. AKM 3455/S1) is expensive and
mediocre; not only is it somewhat difficult to follow, it is
also fraught with errors. However, the electrical section of
the Supplement has descriptions and diagrams for individual
systems, and this alone may be worth the price.
The manual you actually end up with may vary according to
what year you ask for. Steve Draper reports on his: "What I
got was the "Repair Operation Manual" for the XJ-S, which
incorporates "HE & 5.3 Supplements" and is printed by
Jaguar Cars Ltd. The book includes supplement A (1979-1984)
and supplement B (1984-1988‡). It is a single softbound
volume and seems fairly comprehensive. The book includes
repair procedures and illustrations, wiring diagrams, and
An aside: If you get the softbound Repair Operation
Manual and later want to tear it apart, holepunch it, and
put it in a 3-ring binder, you will find that it is a metric
sized book -- and won't fit in a standard 8‡" x 11" binder.
If you're in Europe or somewhere, that's no problem, but
here in the US you may find it a bit of a challenge. Better
office supply stores sell "A" size binders, but you'll also
need to get the proper 4-hole punch. Another option is to
drop into a Wal-Mart and buy a photo album intended for the
Kodak Advanced Photo System; these albums are quite a bit
larger than standard notebooks yet retain the standard
3-hole pattern. Having a 3-hole punch with an adjustable
paper stop is a plus, so you can adjust the stop to center
the holes on the longer pages. Just throw the photo sleeves
out, although the section dividers are nice, you'll wanna
keep them to separate the manual from the supplement and the
like. These photo albums have the added benefit that they
are really nice quality; I even found one with a dark green,
gold, and black cover that looks like it could have come
Owners with the Repair Operation Manual wishing to work
on the GM400 automatic transmission will need to get a
separate manual for this tranny, as the Jaguar manual (mine,
anyway) covers only the early Borg-Warner automatic and the
supplement doesn't address the transmission at all. Andrew
Kalman suggests "How To Work With And Modify The Turbo
Hydra-matic 400 Transmission" by Ron Sessions, Motorbooks
International, 1987, 224 pages, 300 illustrations. Kalman
says: "It seems quite complete, with a historical overview,
basic maintenance, operation, overhaul, modifications and
Alternatively, you can purchase the actual shop manuals
for the XJ-S, which come as several volumes. If you thought
the Repair Operation Manual was expensive, the series of
shop manuals ought to be good for a major coronary. Not only
that, but you may end up having to buy more books than you
anticipated; regarding the Jaguar repair manuals for later
cars, Richard Mansell shares his experience: "Now that I
have the manuals in my hot little hands it appears to be
more complicated than I thought. The pre-H.E. to 87-88
manuals (JJM 10 04 06) appear to be based around the
pre-H.E. with extra sections to cover the differences
between these and the H.E. (pretty logical so far). The new
manuals, up to 91, (JJM 10 04 06-20) come in 5 volumes
rather than the earlier 4 but only appear to cover the
additions since the earlier manuals for the 5.3 plus a
random selection of the original information. Oh, and it
covers the 4.0 engine too.
"In other words, if you have an '89 to '91 5.3 and you
want to know about the new ignition, etc., you will need
both sets as the later volume set refers to many sections
that only exist in the earlier set; e.g. under the heading
"Cylinder heads overhaul" it says:
and right hand cylinder heads, see 12.29.01.
Where is 12.29.01? Only in the earlier set!
"Since the five-volume set costs more than the earlier
one, I assumed it would be a complete guide to the later
"I understand that there are add-ons, JJM 10 04 06-201
and 202 that cover models '92 to '96. 6.0L engine plus other
The Haynes manual #478, "Jaguar XJ12 & XJS" is a
lot cheaper, to the point where you might as well
pick one up even if you plan on buying the Jaguar books
anyway. It's based on portions of the factory manual with
some photos of a teardown of a Daimler Double Six added. It
benefits from some recall and technical bulletin info that
does not appear in the Jaguar books. It also includes
some basic procedures for the GM400 automatic. It only
covers up to 1985, though, so owners of later cars will not
get any info on the ABS brakes, Marelli ignition, etc.
Classic Motorbooks catalogs lists a Haynes manual titled
"Jaguar 12-Cylinder 1972-85", but this is actually the same
book -- they merely misdescribed the title.
PRIMERS: If you are new to
automotive tinkering, you should buy one of the many books
on the market explaining general procedures for car repair.
While this book is written to be as clear as possible, it is
not intended as a primer and no efforts are made to explain
standard auto repair procedures. For example, this book may
describe in great detail how a particular electrical
component has a history of shorting out at a particular
spot, but it will not provide any instructions on how to use
a VOM to track down a short. Quite the contrary, the reader
is expected to know how to track down a simple short, so
failures that are easily isolated and corrected may not even
OTHER MANUALS, ETC.:
Jaguar also makes parts manuals; for example, according
to Stephen Wood, "Jaguar Parts Manual, RTC-9109-B, for the
XJ-S, 1976 to 1982, pre-H.E. cars." Many owners suggest
these books are more helpful to the mechanic than the
repair manual; they contain exploded views of about
everything, which are often easier to understand than the
step-by-step text in the repair manual. And it helps to know
the part number of what you need when placing a parts order
by phone; many mail-order catalogs have lousy illustrations,
and many parts shops carry more parts than they list in
Richard Mansell bought a parts manual -- "...the Jan '87
to late-'89 parts book (RTC9900CA). IMHO this is laid out a
lot better than the earlier parts manuals as it has a
description for each item on the same page as the pretty
picture. If you have an '87 to '89 3.6 or 5.3 XJ-S this
guide is well worth getting, especially to aid
Owners who don't have an owner's manual might want to get
one; it's more complete than most, with wiring diagrams and
According to Loren Lingren, "...Jaguar supplies wiring
diagrams called "Electrical Guides". They are supplied
individually by year, and IMHO are better than the diagrams
that are supplied with the shop manuals. Here is a partial
list by Jag publication number:
"I believe these are much more reasonably priced than a
complete shop manual."
Alldata once offered a CD-ROM on the XJ-S. According to
Michael Minglin, "It is my understanding that Alldata Corp.
provides technical support to automotive repair shops
through a rather expensive computer system. They also offer
individual car support on a CD-ROM. The information on this
CD is more and less than the factory service manual.
"In some areas it is rather sketchy and is missing many
of the things listed in the service manual. On the other
hand it has excellent wiring and vacuum diagrams. It has
clear drawings showing where parts are located and what they
look like. It has some excellent drawings of components. It
has a section listing the hours and estimated parts costs
for many repair jobs. It also has technical service
bulletins that often do not find their way into the Jaguar
manual. Most sections offer a description of how that system
works as well as repair and service procedures. There is a
section offering specialized tools, mostly from Snap-On or
"On balance I consider the Alldata CD a valuable addition
to my factory service manual, but not a replacement for
"My CD is labeled: "ALLDATA FOR WINDOWS", part No.
PN-099-220-R3, 2/96, Imports A-Z 1982-87, All makes Acura
through Yugo, Customer support 800-859-3282. It includes a
plug-in that allows me to access my '84 XJ-S. It seems the
CD contains data on many cars, but you must buy the plug-in
for each car you want to access. I can access data on the
1984 Vanden Plas, XJ6 and XJ-S."
Unfortunately, it may be difficult to get Alldata to sell
you this CD-ROM. Minglin tried to obtain more copies for
others, and reports: "I talked to Gary at Alldata who
claimed they had never offered a CD for the Jaguar. When I
insisted they did, and gave him the part number, he then
stated that they had discontinued that CD. I could not get
to anyone above Gary who could make a decision. My guess is
that if enough Jag-Lovers contact them it should not be a
big deal for them to run some duplicates of the CD. After
all they already have all the data on a disk."
MAIL ORDER CATALOGS: To
those just getting started with the XJ-S, take this bit of
advice: order at least two mail-order catalogs immediately;
a good selection would be Special Interest Car Parts and
XK's Unlimited. You will want to have such catalogs on hand
even if you never order any parts just so you can tell when
some unscrupulous repair shop is trying to rape you on parts
It is also suggested that the owner order a catalog from
Gran Turismo Jaguar. All it costs is the phone call. Even if
you never intend to do any high-performance work, you may
decide to replace broken items with performance stuff
instead of the stock parts. And, besides, it's a lot of fun
to flip though this catalog and dream! And you can show the
spouse how much money you could be spending!
OTHER BOOKS: Richard
Mansell suggests: "For XJ-S fans there is a book by Paul
Skilleter called Jaguar XJS: A Collectors Guide (ISBN
0-947981-99-3). It is full of pretty pictures (nearly 200)
of XJ-S's and variants. There is a fair bit of history
detailing specification changes, etc., covering a total of
"Appendix A lists the technical specifications model by
"Appendix B lists the location of the chassis/VIN numbers
and explains what each bit of the VIN means.
"Appendix C lists launch dates and prices.
"Appendix D is a fairly detailed list of production
changes by date chassis and/or engine number.
"Appendix E lists annual production numbers.
"Appendix F lists performance figures.
"If you are into XJ-S's it is well worth a look."
Skilleter's book is published by Motor Racing Publications
Ltd., Unit 6, The Pilton Estate, 46 Pitlake, Croydon CRO
3YR, UK, ©1996.
Victor Naumann recommends Publication #S-58, XJ-S Engine
Performance. "It has photos and diagrams of ignition and
fuel systems, all the controls and switches and a good
section on maintenance procedures, setting throttle plates
and linkage and checking the potentiometer etc."
"Jaguar XJS Gold Portfolio 1975-1988", compiled by R. M.
Clarke, is a collection of road tests, specifications,
comparisons, and reports on racing and other modifications.
It is published by Brooklands Book Distribution Ltd.,
"Holmerise", Seven Hills Road, Cobham, Surrey, UK.
John T. Horner suggests "There is a brochure type booklet
written by Jaguar when the V12 was introduced and which is
sometimes still available: "Genesis of the Jaguar V12". It
has a good official summary of the history and
specifications as well as beautiful color overlay drawings
of an engine cutaway. I think Bookspeed in the UK may still
offer it." This author has acquired a copy of this book; it
isn't much from a maintenance standpoint, but it cannot be
beat for instilling an appreciation of one of the finest
automotive engines ever designed, providing a concise
history and background of the engine's development. From an
XJ-S owner's standpoint, the worst thing about the book is
that it truly applies to the original Jaguar V12 introduced
in the Series III E-type; many of the details changed by the
time most XJ-S's were built. The engine shown in the book
has carburetors, a canister-type oil filter mounted under
the front end of the sump, an oil-to-coolant oil cooler, an
oil pan that is no wider than the bottom of the block, an
alternator mounted backwards so it sticks out the front of
the engine, etc.
"Genesis of the Jaguar V12" is also available from
TECHNICAL PAPERS: The
Society of Automotive Engineers (SAE) maintains a collection
of papers. Paper #720163, by Walter T. F. Hassan of Jaguar
Cars Ltd., Div., British Leyland Motor Corp., is a quite
detailed engineering study of the development of the Jaguar
V12. Of course, the paper predates such later developments
as the H.E. Bob Weisickle points out that SAE papers can be
ordered online on the WWW from: http://www.sae.org/PRODSERV/TECHPAPE/index.htm
or you can call SAE at +1 (412) 776-4970 Monday through
Friday, 8:00 a.m. to 5:00 p.m. Eastern time.
There is a similar paper titled "Jaguar V12 Engine -- Its
Design and Background", also by Hassan, from the Technical,
Administrative and Supervisory Section of the Amalgamated
Union of Engineering Workers (AUEW-TASS), Onslow Hall,
Little Green, Richmond, Surrey.
Roger Bywater says "there is also a similar Institute of
Mechanical Engineers paper by Harry Mundy from about the
same time (1972)."
SERVICE RECORDS: Chad Bolles:
"...just go to any dealer's service dept., give them the
serial no. of your car; they can pull it up on the computer
and give you the available history."
FUEL ECONOMY: Keeping an
eye on fuel consumption is an excellent way to monitor your
car's condition. Since EPA ratings are generally unreliable
in the real world, it is helpful to know what kind of fuel
consumption the XJ-S should have:
For those who like to do their own converting, there are
0.83267 Imperial gallons in a US gallon, 3.7854 litres in a
US gallon, and 1.609344 kilometers in a mile.
The values for the pre-H.E. are based on fewer reports,
but those reports were fairly consistent; apparently the
H.E. was a huge improvement in efficiency over the previous
design! Note that reportedly the difference only occurs
under light (street) use, and with harder running or racing
the economy difference diminishes.
Of course, the standard disclaimer: "Your mileage may
vary." But you know if you are driving harder or under worse
conditions than the average driver, and if you think your
fuel mileage is worse than it should be you should
immediately investigate the causes. Many of the common
causes also result in major engine damage if left
Note also that some areas require the use of "oxygenated
fuels," sometimes just during particular seasons. Oxygenated
fuels result in far worse fuel consumption.
THREADS: The British invented
the inch/foot system of measurement, so most of the
fasteners on the pre-1984 XJ-S are English fine thread (UNF
or National Fine), available in any hardware store. Jaguar
and other British cars extensively used fine threads, as
opposed to the coarse threads (SAE or National Coarse)
normally used on American cars. Coarse threads are sometimes
used in aluminum parts, because aluminum is too soft for
effective use of fine threads.
In 1984, many of the fasteners within the engine itself
changed to metric sizes. Notably, just about every 5/16"
stud appears to have changed to M8, according to David
Thanks to a continuing effort towards metric standards,
there are metric fasteners in other parts of the car as well
-- even in the pre-1984. Many of the subcomponents, such as
the alternator, air conditioner compressor, and stereo are
made with metric threads. Later cars seem to have more and
more metric threads. Mike Morrin says, "The nuts holding the
wiper blades are the only metric fasteners I have found on
my 1975 car."
There are no reported cases of obsolete British threads
such as Whitworth being found on the XJ-S.
STUDS: Jaguar studs sometimes
have fine threads on both ends, and are therefore difficult
to find locally. Most studs in the US have coarse threads on
one end and fine on the other. You can, of course, order
studs from a Jag mail order outfit -- they're even
reasonably priced. If you want to get on with the job and
not wait on the mail, however, you can find a very long stud
or bolt at your local auto parts store on which the fine
threaded end by itself is longer than the entire Jaguar stud
(many Jaguar studs are rather short). Simply cut the end off
and dress up the threads. Thread the sawn end into the part,
leaving the factory-made threads for assembly.
WASHERS: The V12 engine is covered
with an unusual type of 5/16" washer, C30075/2, that has a
spiral serration pattern on it and is slightly dished. This
washer serves the purposes of both a flat washer and a lock
washer. While the serrations may help prevent nuts and bolts
from unscrewing, the real locking feature is the dishing; it
makes the washer springy, keeping tension on the
David Johnson found an acceptable substitute for the
spiral groove washers: "I found at Pep Boys an 8MM spring
washer. It's part number is 153-0800. They are in the racks
of boxed hardware." Note these washers don't look much like
the spiral groove washers; they have no serrations and are
sprung the other way -- they're not dished, they're wavy.
They are dirt cheap, though. If you find an auto parts store
with a Dorman hardware case, Dorman sells essentially the
same type wavy 8mm washer as part number 436-008. Nobody
seems to sell wavy spring washers in SAE sizes, but 8mm is
essentially the same as 5/16".
The V12 also uses a few 1/4" spriral groove washers. A
6mm wavy spring washer (153-0600 at Pep Boys, 436-006 in a
Dorman case) will fit a 1/4" bolt perfectly and serve
Note that it is always recommended to use some
sort of flat washer whenever a bolt head or nut tightens
down onto aluminum. If you find any places on your engine
where a fastener is tightened onto aluminum without a
washer, it is recommended that you provide a washer.
Conversely, lock washers are only required in certain
places. For example, the head studs require no locking
feature because the tension on the stud is carefully applied
with a torque wrench and the designers have ensured that the
assembly will never allow the stud to become untensioned in
operation. As a general rule, lock washers are required on
very short bolts or studs but not required on longer ones
because the longer fasteners provide enough spring to absorb
transients without unloading.
ANTI-SEIZE COMPOUND: Since
the XJ-S has many bolts and studs threaded into aluminum, be
sure to keep a supply of anti-seize compound on hand. The
stuff is a lubricant with tiny particles of soft metal in it
-- usually copper, nickel, or silver. Use it anytime steel
is threaded into aluminum, to prevent galvanic corrosion
from seizing it up. It also works great on exhaust manifold
studs. The fact is, many experienced mechanics (including
the author of this book) swear by the stuff, buy it in
one-pound cans at better hardware stores (auto parts shops
usually carry it only in small tubes) and use it on
SO YOU FORGOT TO USE ANTI-SEIZE
COMPOUND LAST TIME: Steve Hammatt describes a product to
get stuck bolts loose: "The division is called National
Chemsearch and the product is called "YIELD" and is quite
unbelievable in loosening rusted nuts, bolts, etc. Their
number is 1-800-527-9919. Their salesmen are everywhere
including (believe) even in Russia!
"The key is to use a true penetrating product that has a
lubricant, plus time. Leave it on for at least an
hour, then return and proceed."
Other folks swear by Liquid Wrench, and even WD-40 has
its admirers. Whatever is used, allowing adequate time to
soak in is always required.
Heating a bolt with a torch is also suggested as a method
for loosening, but obviously it's a good idea to wipe the
penetrating oil away first. It also is a good idea to
replace the bolt/nut, since the heating may destroy the
Apparently, some silicone sealants can corrode metal
parts. Jan Wikström says: "To quote the famous Castrol
ad, silicones ain't silicones. Some leave a residue of
acetic acid as they cure, which is a very weak acid but
could conceivable harm bare metal. The trick is to buy
Ed Mellinger says: "Silicone sealant isn't permitted in
most aircraft applications for this reason (among others).
Two neutral-cure silicones I know of are Dow Corning 3140
and 3145; one's an adhesive and one's a thinner "coating",
but I'm not sure either is designed to be an engine gasket
so buyer beware. Warning... they are priced like aircraft
"In the "among others" category is the tendency of
silicone to squeeze out in a bead and then peel off in
strings... possibly into your engine oil on its way to a
bearing! This definite no-no is the most cited reason I've
heard against use of silicone in, er, sensitive areas."
DRIVE-ON RAMPS: The need to get
under a car is inevitable, and for those of us who don't
have access to a garage with a lift, drive-on ramps appear
to be a good solution -- cheap, easy to use, and sturdy
enough to hold a 4000-lb Jaguar without dropping it on its
owner. However, most ramps appear to have been designed for
cars from another era, and the spoiler pushes them away long
before the front tires get near them. Patrick Krejcik
provides a solution: "I got the $17.95 specials, and all I
had to do was to put a 2x6, about 18-24 inches long on each
ramp to lengthen the slope. I used a nail in the end of the
2x6, bent it and stuck it in a hole about half way down the
original slope, and made the slope longer and more
If you wanna get fancier, Mike Wilson says that Griot's
Garage offers a "ramp extension kit".
CHECKING FOR CRACKS: Jan
Wikström provided this "backyard Magnaflux test" for
checking for cracks in steel parts: First, the area needs to
be clean and smooth, so polishing may be required first.
Allow a large, powerful horseshoe magnet to latch on to the
part across the area to be checked. Now dribble kerosene
with iron powder (collected from grinder) over the area; any
crack will show up clearly.