XK8 / XKR ( X100 ) 1996 - 2006

What is the dumbest engineering design on XK8/R?

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  #21  
Old 06-19-2024, 07:02 PM
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But, despite them all, we love them.
 
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  #22  
Old 06-19-2024, 08:06 PM
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Originally Posted by JACKP
Radiator expansion tank hidden behind wheel with no access.
Fake gauges.
Heater hose that requires removal of intake manifold for replacement
Almost impossible to reach fuel lines on fuel tank
The one by the wheel is called an atmospheric tank while the one under the bonnet is called the expansion tank.

hey, don’t hate me, I didn’t make up these names.

in all fairness to the designers and engineers, these cars are twice over their intended lifespan. Most of the items mentioned here worked fine 10 years ago,

Z
 
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  #23  
Old 06-19-2024, 09:28 PM
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Originally Posted by zray
The one by the wheel is called an atmospheric tank while the one under the bonnet is called the expansion tank.

hey, don’t hate me, I didn’t make up these names.

in all fairness to the designers and engineers, these cars are twice over their intended lifespan. Most of the items mentioned here worked fine 10 years ago,

Z
I think about how most automobiles go to the scrap yard after a few years. Ain't gona happen to these no matter how old they get.

Jack
 
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  #24  
Old 06-19-2024, 09:41 PM
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Originally Posted by zray
The one by the wheel is called an atmospheric tank while the one under the bonnet is called the expansion tank.

hey, don’t hate me, I didn’t make up these names.

in all fairness to the designers and engineers, these cars are twice over their intended lifespan. Most of the items mentioned here worked fine 10 years ago,

Z
I have no issues with this "dual tank" system. Lots and lots of cars with "non-sealed" cooling systems had them. During the Reagan administration. The thing that makes me scratch my head is that this was supposed to be a cutting-edge luxury coupe, with a price tag of $80K in Y2K dollars. Yet the cooling system design, the charging system design, and the stereo system, just for three examples, are straight out of the late 80s, early 90s.
 
  #25  
Old 06-19-2024, 10:13 PM
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Originally Posted by blindside
The crappy charging/electrical system where if I don't drive my car for a week then the battery is dead

I think that’s just your car. I can leave my car un-driven for a month, without a battery tender, and it still starts back up just fine.

I do have an AGM battery.
 
  #26  
Old 06-19-2024, 10:20 PM
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Originally Posted by giandanielxk8
I think that’s just your car. I can leave my car un-driven for a month, without a battery tender, and it still starts back up just fine.

I do have an AGM battery.
I agree, no trouble with my AGM either.

(Although I do use a battery tender and drive frequently).

But if a battery goes flat in only a week then something is amiss.
 

Last edited by zray; 06-19-2024 at 10:26 PM.
  #27  
Old 06-20-2024, 02:17 AM
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For me, it’s the rear seat space. Perhaps the most recognised design compromise of the X100.

When I changed my fuel tank, I found space that could have been better used. The rear bulkhead (on a Coupe) could be 2.5 inches further back. It would need a re-profiled fuel tank and reduced area rear seat backs. However, this would place rear passengers farther back where the headroom is 1 inch less.

Also, the front seat-backs seem unnecessarily thick which reduces rear knee room. There is about 1 inch wasted space behind the internal airbag unit and lower headrest motor. Finally, the design of the front seat low-level mechanism necessitated a plate that reduces rear foot space.

Annoyingly, all of these design compromises were fixed by Porsche on their 911 many years earlier ☹
 
  #28  
Old 06-20-2024, 04:09 AM
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Originally Posted by scottatl
Why do you say the control arm is a fail?
Poor choice of materials and no protection against water ingress. Water wicks along the pivot bolt and into the bushings. The bolt shank is unprotected so it can rust in the middle , and the bushing inner sleeve should have been stainless steel.

If the bushing seizes up it can cause the pivot bolt to rotate, which makes the bolt holes oval on a very expensive aluminium crossmember.

I was lucky when I changed them, but I've read some horror stories on here around getting the pivot bolt out.

I have it as a periodic maintenance item.

 
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  #29  
Old 06-20-2024, 10:01 AM
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Originally Posted by PKWise
For me, it’s the rear seat space. …”

in many states in the USA, and possibly many other countries also, insurance rates are significantly higher for 2 seater cars.


The “do-nothing” rear seats do keep the insurance rates low(er).
 
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  #30  
Old 06-20-2024, 12:41 PM
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Since all the good ones have been taken I will have to say the volume control on the radio. Cant control base or treble. I had to send mine to England for some to fix it and put Bluetooth in it.
 
  #31  
Old 06-20-2024, 08:26 PM
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Best ones mentioned sooo…….


coupe headliner fabric glue. Period. I mean every single one…. Like wtf Jaguar? Come on lol
 
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  #32  
Old 06-20-2024, 11:16 PM
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Reading through these, there is a definite penny drop of - this was a cobbled-together compromise of a car, I get it. Its an almost bizarre mish-mash of parts old and new spanning 3 decades. Brand-new (too new) engine design. CANBUS. IRS from the 60s (one of the better features, mind). AC from Honda, I think. Various random honda parts. Mercedes transmission. Bosch power steering. Warmed-over XJS monocoque. Lacklustre infotainment and bolted-on satnav. but the seating position could most definitely have been done better, I mean the seats in the XJS are objectively better. The seats in the early XK8s with the fixed backs are at least thinner. Ultimately, Jaguar did not have enough money and time for this car and the X150 to me, now, represents a better realisation of what the XK is meant to be because it also got a totally reworked chassis.

A pox upon the designer of the rear diff housing esp on the convertible. Two days it took me to get that ******* plug off. Had to drive 75 miles to get a special tool, but I resisted cutting a hole. Changing the O2 sensors was a pig, not least because the fault code was a lie and it wasn't the fuel pump and I had to work that out. And even more ridiculously, that was a pleasant surprise - much as I hated changing those O2 sensors it was a relief not to have to do the fuel tank. According to the service history, my car had a failed fuel pump at 20k miles that got changed, so I hope I never have to...

Yet, I knew most of this before I bought an X100 with a 4.0 and still did it because - its a pretty car. I even sought out the earlier 4.0 (2002) because I don't like the body kit and front clip on the later ones. And I get an almost masochistic thrill out of daily driving one and working on it myself and keeping it on the road. I love how people react to it - "don't see many of those these days" "Is that the supercharged one" "that's a beautiful car". And its made me a better home mechanic. If it wasn't for this community and the resources here I would have sold the thing at a loss and cursed its name ever since.

So yeah, the best thing about the X100 is the friends you make along the way lol.
 
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  #33  
Old 06-21-2024, 03:21 AM
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Originally Posted by zray
in many states in the USA, and possibly many other countries also, insurance rates are significantly higher for 2 seater cars.


The “do-nothing” rear seats do keep the insurance rates low(er).
The rear seats are big enough for young children and luggage. The car is much more practical than a 2 seater.
 
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  #34  
Old 06-21-2024, 03:42 AM
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Originally Posted by stevis05
coupe headliner fabric glue. Period. I mean every single one…. Like wtf Jaguar? Come on lol
Don't be too hard on Jaguar other than choice of material, and they were definitely not alone. My son's 1991 MK2 Golf, the XK8 and Mrs. H's X5 have all suffered. The foam layer eventually decomposes to dust so everything descends.

The headlining in my 27 yr old Peugeot beater, however, is still as good as the day it came from the factory.
 
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  #35  
Old 06-24-2024, 03:55 AM
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Wasn’t meant to be too harsh on jaguar, I mean, if I didn’t like it I wouldn’t own the car and continue to make it better. I bought my car because I WANTED it, and knew EXACTLY what I was getting into, like I’ve said before; if you own an older Jaguar and aren’t prepared to work on it more than you drive it… it’s not for you ( unless paying top dollar to rectify every little issue is nothing), and if that’s the case, you should probably get a Maserati or Aston Martin or Alfa Romero or something, maybe a Bugatti? Those of us who own, fix, maintain older jags or even try to improve can all say at one thing(for the most part); we’ve taken it apart, accepted its inadequacy , said we can overcome and improve it, researched it, and made an effort to. Fail or not, doesn’t matter, we tried. That’s what matters, again, wasn’t trying to knock Jaguar or anything, I was just chiming in, didn’t think I would be called out on it, it was a harmless thread. Sorry if I offended someone but it is what it is, my coupe came to me with about 30 thumbtacks holding the headliner up…..

imean if you want a fresh suggestion what about the e brake lever position? Or the fact that it can’t sit more than three weeks without killing a battery? Group 49 agm at that! how bout the millions of parts upgrades throughout the vins?

nothing says I was supposed to be the next Aston Martin db like the xk8…. But to those of us who love and respect these…. Who the f…… cares?
 
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  #36  
Old 06-24-2024, 07:46 AM
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Originally Posted by stevis05
Those of us who own, fix, maintain older jags or even try to improve can all say at one thing(for the most part); we’ve taken it apart, accepted its inadequacy , said we can overcome and improve it, researched it, and made an effort to. Fail or not, doesn’t matter, we tried. That’s what matters, again, wasn’t trying to knock Jaguar or anything, I was just chiming in, didn’t think I would be called out on it, it was a harmless thread. Sorry if I offended someone but it is what it is, my coupe came to me with about 30 thumbtacks holding the headliner up…..
No disagreement here: I certainly wasn't calling you out, and I don't think anyone has been offended - I certainly haven't.

As Rex says, "we still love 'em".
Warts 'n all...
 
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  #37  
Old 06-24-2024, 10:26 AM
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Some parts definitely needed better engineering or more longevity and endurance testing.

However, it's amazing how robust some other parts are.

The 4.2 supercharged engine on mine, after 20 years, still runs like new. Also, although material choice may have been subpar in some areas, or compromises due to comfort in others, if compared to some of the stuff being sold today, I'd say we're pretty good. These cars do keep us busy, but they don’t become complete jalopies necesitating the junk-yard or a rebuild at 200k.

At least we don't have plastic oil filter housings, plastic timing covers, or plastic anti-roll bar drop-links (I'm looking at you, BMW and Stellantis cars).
 

Last edited by giandanielxk8; 06-24-2024 at 10:29 AM.
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  #38  
Old 06-24-2024, 10:32 AM
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Originally Posted by Throwback
Had to drive 75 miles to get a special tool, but I resisted cutting a hole.
Not to hijack this thread, but could you post the name, or pic, of that tool? I need to check my diff.
 
  #39  
Old 06-25-2024, 07:29 PM
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A number of people cited plastic parts, I agree they suck. I have had to make many workarounds and try to rebuild or refashion them, but I consider those more bean counter issues than engineering issues. Those shmucks saved a few hundred on parts on a $100k car that was destined to be a classic, what dopes.

I
 
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Old 06-26-2024, 06:02 AM
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Not sure the frustration with failing parts and aging brittle plastic bits would be much different with most luxury cars of that era. Each has its own shortcomings. Remember the XK8 “evolved” considerably over its production run. That said, I still prefer the earlier X100 styling better. The design remains a “Wow, that’s a beauty” head turner after 25+ years!
 
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