Jaguar XJ-S. Manual - part 62

 
 

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Some hose assemblies in the fuel system have clampless barbs to connect metal tubing to hose, similar to those fittings 
on the rail described above.  However, these may have a deep cup covering the end of the hose instead of the dished 
washer used on the injector hoses; this deep cup looks like a crimp collar except that it isn’t crimped.  The deep cup can 
make it a bit more difficult to get the old hose off, since getting the razor knife on the hose will be all but impossible 
and getting a soldering iron tip in there will be no picnic either.  To make life easier the next time you replace hoses, 
you might want to order some of the dished washers used on the injectors, EAC7876, and reassemble the fuel lines with 
these instead of the cups.  That will also make disassembly easier this time, since you can just cut the cups off to get 
them out of your way. 

If you get those cups off intact and intend to reuse them, note that when putting the new hose on you may have trouble 
telling if it’s on all the way.  So, prior to assembly, slip the cup onto the end of the hose and mark on the hose so you’ll 
know when it is fully inserted into the cup.  This is especially important with a really thick-walled hose like the 
Weatherhead cloth-surfaced stuff described above because it fits so tightly in the cup that it makes it very difficult to get 
on the barb. 

The author’s solution here worked well.  I used a hacksaw to cut these deep cups circumferentially, separating each one 
into a sleeve and a shallow cup -- obviously being careful not to saw all the way through the hose and damage the barb 
underneath.  I was then able to simply slide the sleeve up the hose out of the way and slice the hose away using the 
same method as with the hoses on the rail with the dished washers.  When reassembling with new hose, I reinstalled the 
shallow cup (cleaned up a little) and discarded the sleeve.  The finished assembly looks good, arguably better than the 
dished washers at the rail. 

 

 

Fuel Tank and Filler 

 

 FUEL FILLER CONFIGURATION:  In the 70’s, the fuel filler pipe on the XJ-S had a flange on it and was rigidly 
mounted behind the filler door with three screws.  This author’s ’83, however, has no flange; all it has is a small tang 
that engages a small bracket to prevent the filler pipe from rotating as the cap is tightened.  The same three screws are 
used instead to fasten a metal collar that holds a rubber boot around the filler pipe.  Hence the filler pipe is mounted 
flexibly; it can move around a bit since it is held in place only by the boot, an O-ring seal at the tank, the hose clamped 
onto its outside, and of course that little tang that prevents it from rotating. 

With either design filler, the clamp on the hose connection to the tank is accessible from within the trunk by removing 
some carpet.  Then you can pull the filler out through the filler door after removing three screws. 

On the later design, the filler itself inserts into the opening in the tank with a really fat O-ring for a seal, and then the 
entire assembly is enclosed in a short section of 2” hose.  If the fat O-ring works, the 2” hose only serves to hold the 
assembly together, not to contain fuel or odors.  This assembly might have been designed this way because Jaguar 
couldn’t find a 2” hose that would positively prevent fuel odors.  Remember, the fuel-filler-to-tank connection in most 
other cars is underneath the car, not inside the trunk -- perhaps for good reason.  If you have odors, you might consider 
pulling this assembly apart and replacing that O-ring, which is part number C46157. 

 

FUEL FILLER CAP:  ...is discussed on page 259 under the vapor recovery system. 

 

FUEL FILLER DRAIN:  Derek Hibbs says:  “The answer for my fuel smell was simple:  the fuel cap overflow pipe 
was disconnected and any spillage during refueling was draining directly into the boot/trunk instead of onto the ground. 
 Reconnected the overflow pipe and no smells (I also take more care when refueling).” 

 

 
 

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STEENKIN’ RIVET:  On the underside of the car there are numerous lines that are held to the car with little clips and 
rivets.  One of these rivets is in the panel the tank sits on, and sometimes the weight of the tank compresses the pad 
enough that the metal tank contacts the tip of the rivet.  After some vibration, the contact can wear a hole in the bottom 
of the tank.  Once the tank is drained and removed, it is a simple matter to patch the hole (there are types of epoxy sold 
that will work well) and find an alternate way of supporting the line under the car. 

 

STRESS CRACKS IN TANK:  Officially, the recall supposedly was to prevent excessive pressure/vacuum cycles on 
the tank, resulting in stress cracks.  Obviously, this is something else to check on your tank. 

 

RUSTY TANK:  Chad Bolles reports that the seal around the rear windshield starts leaking, and the water soaks the 
sponge under the tank and causes the tank to rust.  Chuck Sparks reports that external rust on the bottom of the tank 
where it sits on that foam is far and away the most common cause of fuel leaks in the trunk he has seen.  The author’s 
car didn’t have any leaks there, but it did have some rust -- and there were no signs of any leakage from the rear 
windshield.  It’s entirely likely that filling the tank with cold fuel -- or just running the car, which chills the fuel in the 
tank via a fuel cooler -- may cause condensation on the outside of the tank, which runs down the sides and soaks into 
the pad. 

 

FUEL TANK DRAINING:  The way you’re supposed to drain the tank is to remove a rubber plug in the floor of the 
trunk and loosen a drain plug in the bottom of the surge tank and allow it to drain into a container.  The drain fitting 
works kinda like a big brake bleed nipple; you don’t need to remove it, just loosen it a coupla turns.  Unfortunately, the 
drain never lines up with the hole in the bottom of the car very well; you might want to consider enlarging the hole and 
using a larger plug.  Hopefully, one way or the other, you can push a short piece of 5/16” tubing onto the drain fitting to 
route it out the bottom of the car and into whatever container you’ll be collecting it in.  Kevin Darling says, “An 11/16" 
wrench easily opened the sump drain from within the trunk.”  While you’re fiddling with that drain, you might consider 
upgrading it as described on page 252. 

Using that drain works OK, I guess, but there is an easier way!  Remove the spare tire and disconnect the line from the 
inlet to the fuel filter.  Direct this line into a gas can sitting in the trunk.  Remove the fuel pump relay and insert a 
jumper in the socket between terminals 30 and 87, which will run the pump and run all the fuel into the gas can, neat as 
you please. 

Of course, either way you drain the tank, it’ll be easier if you drive the car until it’s really low on fuel first. 

 

FUEL TANK REMOVAL:  The main fuel tank is located over the rear axle.  It is accessible by removing the spare tire 
and some other stuff, then pulling the carpet out.  Tank removal is pretty straightforward until you get to the last step.  
The tank sits on a 1/4” layer of foam, and is often bonded to the foam from years of sitting on it so there’s no way you 
can slide it out.  Chuck Sparks offers a solution: a machete!  Just slice through the foam from wheelwell to wheelwell, 
and the tank will come right out.  You’re probably going to want to replace that foam anyway; if the tank has been 
leaking, it’s probably smelly. 

 

FUEL TANK LINING:  The fuel tank in the XJ-S is made of stamped sheet steel.  This is a sorry choice of material for 
a fuel tank, and any automaker that chooses it should be ashamed -- and that’s most of them.  It’ll start putting rust 
particles into your fuel system almost immediately.  After it’s been doing that a few years, things get more serious.  It 
may develop leaks due to rusting from the inside out; it may develop leaks due to rusting from the outside in; it may 
develop leaks due to stress cracking; and it may shed enough rust scale from the inside surfaces to plug the fuel pickup, 
resulting in fuel starvation at high power, which in turn results in burnt pistons. 

If you already have such problems, you need to do something -- but if you don’t have such problems, you might still 
consider making some preventative measures at some convenient opportunity.  A popular strategy -- for owners of any 

 
 

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old cars with steel fuel tanks, not just Jaguars -- is to apply a coating to the inside of the tank.  Most such coatings will 
not only prevent future problems, but they will usually seal up minor leaks.  John Whitehead says “I have used gas tank 
sealer from Bill Hirsch Automotive (see page 697), with great success.  I put it in the fuel tank of my ’67 XKE which 
had a number of pinhole-size leaks.  Previous attempts to coat the outside of the tank were not as successful.  The tank 
sealer is gasoline and alcohol resistant.  A quart can is sufficient as only a thin film is coated to the inside of the tank.  I 
am not sure of the product’s chemistry, but it dries to a white Teflon-like film.”  Obviously, major cracks or holes will 
require more extensive repairs. 

Other sources of similar tank sealer materials include Red-Kote by Damon Industries, Renu (page 701), Eastwood 
(page 701), and Avon in England.  Most modern sealers claim to be suitable for gasohol, but you might want to ask to 
make sure.  Oxygenated fuels, octane boosters, lead substitutes, injector cleaners, and anything else you may be 
tempted to put in there are also things to ask about.  The Hirsch, Red-Kote, and Eastwood sealers (and perhaps others) 
use methyl ethyl ketone as a solvent, which means you need to avoid putting anything with MEK or acetone in it in 
your tank.  Note that, in the case of oxygenated fuels, lining the tank may be an improvement; MTBE will attack the 
brazing on a steel tank. 

Several people have reported using POR-15 to coat the inside of their tank.  It may not be specifically intended for the 
purpose, but nobody has reported any problems. 

You should be warned that lining your own fuel tank is not an easy job for the novice.  Obviously, the tank must be 
removed from the car, but that’s not the hard part.  The inside of the tank must be scrupulously cleaned prior to 
applying the liner, and cleaning is a serious challenge on the XJ-S tank -- even for shops with lots of experience 
cleaning and sealing fuel tanks.  The XJ-S tank has so many baffles inside that, looking into the filler and fuel level 
sender openings, you will not be able to see more than perhaps 1/4 of the total interior surface of the tank, even with 
mirrors.  You can just forget about brushing, scrubbing, sandblasting, or the like.  The only way you’re gonna do 
anything inside this tank will be by putting things in, shaking it around, and pouring it out. 

Bill Eslick:  “Many years of racing (Midgets and Sprint cars) have given me opportunities to learn how to clean a fuel 
tank.  Solution:  Three pint-sized cartons of BBs.  Pour them in the tank and shake the shit out of it.  If you are going to 
coat the thing then shake it dry.  Rinse with lacquer thinner, and shake again.  This is tedious but works remarkably 
well.  Be sure you use BBs; lead shot can get lodged in baffles, etc. because it's so soft.  Also, any errant BBs can be 
pulled out with a magnet.” 

A report from this author, who has tried BB’s: if you put a BB in the XJ-S tank, you will be using a magnet to remove 
it.  They will not come out any other way.  That doesn’t necessarily preclude the use of BB’s; once you figure out how 
to use a magnet effectively, it only takes a couple of hours (!) to get a few thousand BB’s out of the tank. 

Unless things are really bad in there -- lots of loose scale -- most owners would be well-advised to use only liquids in 
this tank.  Still, this is not a simple matter of pouring out the gas and pouring in the sealant.  Mike Aiken provides the 
guidelines recommended for use with the Eastwood product: 

1.  Wash tank with hot soapy water, then rinse out with a garden hose. 

2.  Metal wash diluted in 2 gallons of water.  Slosh, 5 minutes a side, slosh.  This is supposed to remove 

contamination from surfaces and inhibit flash rust.  Says it contains alkali surfactants(?). 

3.  Rinse with garden hose. 

4.  1/2 gallon of muriatic acid obtained locally.  Slosh until gray appearance. 

5.  Rinse with garden hose. 

6.  Rust remover (phosphoric acid).  Rotate until all sufaces are contacted and uniform gray appearance(?).  

Dump out. 

7.  1 quart of acetone obtained locally.  Slosh on all surfaces (no specified time).  Dump out. 

8.  Do step 7 again. 

 
 

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9.  Sealer.  Rotate all around.  Let stand 8-10 minutes on each side.  Dump excess.  A white coating should exist 

on all surfaces of the tank.  Says it contains methyl ethyl ketone. 

10.  Allow to dry (open) for 48 hours before use . 

“If you dumped all this crap in the ground you would have another "Love Canal".  It says to dispose of "stuff" 
according to local law.” 

The instructions that come with other products may not be as extensive, but they should be.  Simply applying a single 
cleaning product prior to lining may work on a new tank, but it’s likely to result in troubles down the road if done to an 
old tank with a few years’ accumulation of surface rust and gasoline varnish inside.  The lining may not stick securely 
in spots, then later peel off and plug up the pickup. 

Aiken:  “The key, I believe, is the first step (Ed. note: he means step 2), which is to get all the varnish and other goop 
off the metal.  Rust (and some metal) will be removed by the muriatic acid, but the acid will not remove non-metallic 
stuff.  The cleaner supplied by Eastwood softened but did not remove all the gasoline residual (varnish, etc).  Where I 
could see it I could scrap it off with a stick, so it was not yet removed.  So I added a step.  With most of the cleaner still 
in the tank, I added a gallon of acetone.  Sloshed it around then let it sit for about two hours, then sloshed it again.  It 
worked.  If you see anything but gray metal (maybe some rust and corrosion is OK) the process will fail.  The muriatic 
acid will not remove non-metal stuff, and the liner will only adhere to pure etched metal.” 

The steps above describe a “metal wash” with “alkali surfactants”, but in reality any automotive cleaner/degreaser that 
can be poured into the tank, sloshed around, and drained out will work well.  The objective is to get any varnish and 
goo out, so make sure that you accomplish that. 

The muriatic acid is for getting the major metal corrosion off.  Muriatic acid is available at building supply stores (it’s 
used to clean brick walls) and at swimming pool supply stores (used to control ph in pools).  The concentration 
commonly available is 20º baume, which is a suitable strength for this job.  Most shops -- as well as the guidelines 
above -- suggest using a half gallon, but on this tank a full gallon is advisable because the interior of the tank is so 
convoluted that there may be spots you don’t get to with less liquid inside. 

Muriatic acid is nasty stuff; Aiken says, “muriatic (hydrochloric) acid is potent and very caustic.  Emission of chlorine 
gas is lethal.  You must wear rubber gloves and a mask and be outside.”  Arranging to be upwind is helpful, too, even if 
it requires a fan. 

Phosphoric acid is available in several products for treating surface rust, including Ospho and Right Stuff De-Ruster, 
available at auto parts stores.  It chemically converts rust into something inert and paintable.  Note that Naval Jelly is 
also a phosphoric acid-based rust treatment, but unusable here because it’s too thick to slosh around inside; you need a 
thin liquid here. 

Note that there should be no rinsing with water past step 5.  The residue of the phosphoric acid treatment is removed 
with the acetone.  After rinsing and draining (several times for maximum effect), any remaining acetone will evaporate 
completely in minutes, leaving the tank clean, dry, and ready for lining. 

Tip: each time you put a liquid in, you’re gonna have to drain it out.  And there is only one opening into the XJ-S tank 
that will drain the last pint or so, and that’s the fitting for the main line to the surge tank -- the one that’s intended to be 
a drain.  All the other openings are nothing but frustration, nothing ever seems to pour out of them except when you 
don’t want it to! 

A popular idea is to use heat -- either to make the various cleaning agents or acids work better, or merely to dry the 
inside of the tank after rinsing.  If a really big oven is available, this might work pretty well -- but the more common 
procedure is to use a torch to heat the outside surface of the tank.  One should be aware that this method might be 
perfectly workable on other tanks that are mere cans, but on the XJ-S tank such torching will clearly have more effect 
on the outer shell than on the baffles within. 

Also note that you will only be able to visually inspect or physically touch a small percentage of the inside of an XJ-S 
fuel tank.  That means that you must rely on liquids to accomplish everything you need to accomplish.  Trying to scrub 
the areas you can see will only keep you from being able to judge the success of your work by looking at the areas you