A few general questions about the XJS

So, I’ve been looking at a fair number of cars online and trying to do my research on the car in general.

I had come up with a few questions that I haven’t been able to find the answers for and was wondering if the members here could chime in to answer them if they can?

  1. How come on some jags the wipers go right-to-left and others go left-to-right? I thought initially it might be a RHD vs LHD thing but that doesn’t seem to be the case.

  2. I recently saw a 1988 XJS for sale but the dash looked similar to one found in a XJ6 sedan (the cluster had the 6 gauges, but not the 4 barrel gauges normally seen, it had 4 small round gauges. Was this an option offered?

  3. I thought I read somewhere that the V12 will shut down some cylinders when at speed. Is this true?

  4. Everything I’ve read suggests that overall, the brakes on the XJS are “good” for the car. Are there any modifications or after market kits that can be installed to make them better?

  5. In regards to the rear buttresses on the coupe, are these spaces open through the trunk and can you see up into them with a mirror and flash light to check for rust?

That’s it for now, I’m sure I might have some more as I continue!

If you’ve come here to ask complicated questions about the random production line changes that Jaguar made, then you have quite a few thousands of posts to go through.

That would be the dash from the later 1992 facelift model. It wasn’t an option, someone has retro fitted it.

Not by clever design. But search for “Marelli engine fire” for instances of shutting down cylinders through un-clever design.

There were different ABS systems fitted, quite a bit of work to change them. You can easily upgrade the pads, I use EBC yellow stuff. Front disc upgrades are probably not necessary. Lots of discussion about rear discs - vented or not, inboard or outboard. Recent thread Inboard brake question.

No idea on this one. There are many, many other places you want to be looking at for rust, never heard of any issues with the buttress area.

As far as I know nobody has ever conclusively determined why we see this.

In addition to the previous answer I’ll add that, years ago, it was somewhat popular to convert to Series III gauges. There was a company offering a kit for this but some home-brewed examples were done as well


I found wiper arms that were designed to park on the passengers side (from the UK, so it was the drivers side there) and I reversed the motor to have them park on the passengers side, even though it was designed and delivered as wipers that park on the drivers side. It’s a worthwhile revision to make.

I have a 96, so it might be more/less complicated than the earlier ones.

Arms are different for left and right park, if I recall.

“Marelli engine fire” searched. . Hope my ‘94 XJS 6.0 cylinder is immune. That’s crazy!

You may want to clarify.

If you mean XJS 6.0L - then that would a V12, and prone to possible problems.
If you mean XJS 6 cylinder then you’re all good.

Surely this means that the efficiency of the wiping is better for your passenger than your driver? Given that it’s the parking side that gets the fuller arc of movement?

Regarding my ‘88 LHD with left side park, the arms are cranked slightly at the blade attachment; this makes the blade parallel to the lower windshield reveal molding when the wipers are parked.
I use a 14” blade on the left and a 16” blade on the right arm to maximize area swept without the blade tips hitting the moldings.
I think the intent was to have right part on RHD and left park on LHD, but parts availability may have interfered.

Re: “ You may want to clarify.”

Thank you! Meant the XJS 6 cylinder. Still learning most there is to know about Jags including I.D.s and lingos. Great machines. I’ll drive even if they do “breathe fire” as worse comes to worst- what a way to go, right?

“How’d the hound go?”

“Marelli fire.”

Yes, on my '94 they are hollow. No sign of rust up there I’m happy to say. I used my phone to point in there and get a photo. But what you want to do is point the camera down and try to get a picture of the inside of the rear wheel arch. There can be plenty of rust in there but easy to see when you pull the carpet trim and lean in to take a look.

Thanks for taking the time to answer these guys!

I am trying to spend some time going through the different threads. It’s going to take a bit, LOTS of knowledge here!

Efficiency of wiping? No.

Does the passengers side get more of the windshield wiped? Yes, but its at the bottom of the windshield. If you’re looking there when it rains, then I’m afraid you’ve probably already hit something.

I prefer not looking at the wipers constantly when it’s not raining. If you’re concerned about the reduced wipe, I would think you would be even more distracted by the parked wipers in your way as you drive everyday.

Maintain them. Loads of these cars sit for ages without fluid changes which eventually causes corrosion inside the brake system. Not fun to deal with. You can install vented rear discs, or swap to outboard for better cooling if you want, but there isn’t that much else you can do with them besides fabricating brackets for other brake systems.

The XJS is from a time when 15 inch wheels were big, the brakes are best described as large calipers on small discs. They couldn’t really go any bigger. Neither can you without unfitting wheels.

Not sure if this is relevant to the wiper motor on the XJS, but, IIRC, to get the “uniwiper” on the XJ40s (and, IIRC, X-300s) to park on the opposite side there is a cam or some such inside the wiper housing that, if you flip it over, somehow it reverses things 180 degrees to achieve the desired result.

Most of the brakes in XJS cars - are simply neglected.
You have 12 pots per car, that’s much better than era-equivalent bangers. If they work of course…

Buttresses are inded easy to inspect with mirror, you may need to tear-off some of the British-made dump-it-all bathroom carpets. Easier way is to use inspection camera f.eg. connected via usb to your phone.

The pedal feels hard compared to todays brakes, but they sure do stop the car.

I’ll get you a T-shirt Yanusz
“I :black_heart: British Engineering”


Speaking of which, I had to brake hard the other day for a sudden stop. The brake warning light came briefly on, and went off again just as quickly. The fluid level is up to snuff though and I have checked it with the test strips for both copper contamination (“wear”) in the system and with the laser checker for water contamination %. Passed both of those checks with flying colors. Any idea what is possibly up, or nothing to be worried about? :confused: The steering wheel, btw, went wild with side-to-side movement, too. Again, warped rotor somewhere? :confused:

Do you have any that say “Lucas - Prince of Darkness” on them? :laughing:

Most probably the float is filled with fluid.