Jaguar XJ-S. Manual - part 116

 
 

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Really, you should inform your auto insurance carrier so they can delete any credit you may be getting for having ABS. 
 This author tried that once with no luck; the insurance company’s database showed that that particular model 
automobile has ABS and there’s no way to change that. 

 
 

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BODY 

 

1991:  For the 1991 model year, the body of the XJ-S was significantly altered.  The most obvious differences were the 
totally different taillight arrangement with new “neutral color” taillights that don’t look red until they come on, and 
rocker panels that flared toward the wheel wells rather than being perfectly straight.  But despite the outwardly similar 
appearance of the rest of the car, supposedly almost every panel was altered, so purchasing any replacement body 
panels will probably require specifying pre- or post-1991. 

The more significant change, as far as buyers of used cars are concerned, is that beginning with the 1991 body style 
revisions the entire body was supposedly made from galvanized steel. 

 

RUST:  The following is a description of where to keep an eye out for rust on an XJ-S, courtesy of John Butler, Mike 
Morrin and others: 

•  The joint between the rocker panel and the rear fender. 
•  Lower (i.e. closing) edge of boot (trunk) lid on the inside. 
•  Top dead center of rear wheel arches. 
•  Around rear bumper side-arm mounts (and along the horizontal seam behind them; Check inside the boot). 
•  The lower edge of the panel below the centre section of the rear bumper. 
•  Around tail-lights; just below them down the seam there and just ahead of them on the rear wing. 
•  If your back window rubbers are softening check for: 

ƒ  accumulation of water in the deep wells on either side of the boot (trunk). 

ƒ  water trickling down inside, down the back of the rear seat back and accumulating in the spongy 

sound-deadening underneath. 

•  Around the radius arm mountings  -- structural 
•  On the front wing, just ahead of the front door hinge and just above the rocker panel. 
•  The front end of the sills (or the front of the footwell), behind the front wheels. 
•  Front footwells under the carpets (wet carpet rust). 

Now, about those radius arm mountings.  The way most owners find out they have a rust problem here is that the car 
starts wandering aimlessly at speed!  The front mounting for the radius arm -- adjacent to the rear jacking points -- rips 
out of the bodywork along with a large section of sheet metal, allowing the rear wheel on that side to pretty much go 
where it wants.  How does yours look? 

John Nuttall adds, “I found two places where rust, if left untreated, could cause serious damage: 

1. Chassis rail/tunnel area.  By the chassis rails I mean two heavy gauge steel members that run from near the 
back of the floor right to the front of the engine compartment.  These rails from the backbone of the body.  
The floor and tunnel are made from two separate pieces, one for each side, joined at the top of the tunnel.  
There is a step in the lower part of the tunnel.  The chassis rail is welded to three faces of this step.  The lowest 
part of the rail is horizontal and extends under the floor about two inches.  The two are spot welded together.  
On my 1987 shell the rail was not formed properly so that the part of the rail under the floor slopes 
downwards to the outside.  Looking under the car I can see a gap between floor and rail that was not filled by 
sealer.  Looking at the floor from above I can see depressions in the floor at each spot weld where the tongs of 
the welder forced the thinner floor metal down to meet the rail.  

 
 

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The consequence of all this is that rust has started in the space between rail and floor and has spread to the 
vertical part of the step in the tunnel to such an extent that rust is visible on this part of the step when viewed 
from inside the car.  The rust is eating away this part of the floor/tunnel stamping. 

The serious implications to the structural integrity of the body are obvious.  This fault appears to be caused by 
improper manufacturing of the rail and lack of quality control, and it probably occurred on other vehicles.  

2. Front lower outer seat belt anchorage.  On the ’77 and ’79 cars this anchorage is a nut welded inside the 
vertical face of the inner sill.  Presumably it was thought that this was not strong enough, and at some point 
before ’87 the anchorage was moved to the sloping part of the floor adjacent to the sill.  A thick plate was 
welded and bolted to the underneath of the floor to reinforce the area.  Unfortunately, the floor has a ridge in 
at this point and there is a gap between the floor and the plate here.  The undercoating has proven inadequate 
to stop rust between plate and floor.  This rust has spread between undercoating and floor.  Rust is visible from 
the inside on parts of the floor, which means that rust has eaten through the floor.  The strength of the 
anchorage is clearly at risk.  This fault is mainly due to poor design, I would think, and it is certain to be 
present on many other vehicles. 

“I urge owners of cars that might be affected by these problems to inspect their vehicles.  Inspection from the inside 
requires that carpet and insulation be removed.” 

 

RUST AVOIDANCE - TRUNK LID:  Julian Mullaney sends this tip:  “Beginnings of rust under the lowermost lip of 
the trunk (boot) lid.  There are not enough drain holes here where the two sheets of steel are spot welded.  I will drill a 
couple more drain holes.” 

 

RUST AVOIDANCE - TAILLIGHT AREA:  Julian Mullaney points out that water may collect behind the taillight 
fixtures, since there is no drain from this area.  If it appears to be a concern, perhaps the best solution is to merely coat 
the metal with something to prevent rust, since it doesn’t show. 

The gaskets around lenses on cars generally follow one of two schools of design: they either attempt to totally seal 
thereby not allowing water in, or they include a notch at the bottom to allow water to drain out.  This author’s 
observations and experience indicate that the second idea is more often successful.  Jaguar, of course, uses the first.  To 
drain the water from the area behind the taillights, the gasket between the fixture and the body can be cut prior to 
installation to form a drain channel.  If done at the bottom corner near the boot lid, it will scarcely be noticeable. 

 

RUST AVOIDANCE - GENERAL:  Car enthusiasts generally recommend a product called Waxoyl (see Brit-tec, page 
699) for treating the areas of bodywork prone to rust.  According to Frans Hoekemeijer, “It can be painted or sprayed.  
It can be thinned with “white spirit”, which evaporates rather quickly.  Only a very thin layer is sufficient to protect 
metals against corrosion as the molecules are polarized and cling to the surface through electrostatic action, in the same 
way water molecules do unfortunately.  It sets to a waxy substance.  If used on the outside of the underbody of the car it 
has to be renewed every so often.” 

In the UK, Waxoyl sells a “pump kit” which screws onto to can of Waxoyl and you manually pump it and it becomes a 
spray gun.  It comes with a thin lance so you can poke it into various holes and get good coverage.  Pete Hamel says 
“It’s quite thick at normal temperatures so you can either thin it with white spirit or immerse the can in a bucket of hot 
water to make it more sprayable.   

“The beauty of it is that you do not have to completely clean all dirt off the surfaces you apply it to as it creeps into 
small crevices and through dirt.  It’s good for hard to reach areas.  You can also apply it over surface corrosion (remove 
any flaking rust).  It does leave a slightly waxy/sticky surface though so you don’t want to use it anywhere that 
appearance matters.” 

There are some people advertising in Jaguar World who come to your house and treat the car for you.