Knowhow: Jaguar XJS — problems, performance and reliability

 Jaguar XJS

This guide outlines the background of the Jaguar XJS, its performance and reliability, plus known problems.

The Jaguar XJS is one of the cheapest classic V12 grand-tourers you can get your hands on, but like most old V12 cars, it’s cheap for a reason. Indeed, it’s notorious for very expensive repairs, particularly major issues like engine and transmission failures. But, just like with any other vehicle, regular maintenance, correct car washing, and timely repairs can definitely improveJaguar XJS reliability.

The real problem is that most mechanics won’t work on anJaguar XJS — you’ll have to find an experienced one, which can prove very expensive. Fortunately, you can work on your V12 grand-tourer using a Jaguar XJS repair manual, which will guide you through any repair. It also helps that the XJS isn’t overly complicated, especially the mechanical parts.

Still, you should know that getting this particular classic car can be challenging and will require many hours in the shop. The XJS is less reliable than any modern car, and sometimes it’s impossible to predict what will go wrong next. Today it will be a distributor; tomorrow, it could be the tachometer; the day after, it might start letting water in.

Nonetheless, I understand that the Jaguar XJS has a certain appeal; if you are into buying a British V12 and have time to spend working on it, here are models I’d recommend and a list of the most common issues you should be aware of.

Jaguar XJS V12 vs. Inline-6 — Reliability and Performance

Many forum members will say that it isn’t a Jaguar XJS without a proper V12, but is buying one really a wise decision? Well, as long as the car was well-maintained by previous owners, there shouldn’t be too much difference. That said, a well-maintained XJS, no matter the engine, will have a price tag of well into the five figures. So if you want a well-maintained model for cheap, a straight-six is the way to go.

The main differences are in maintenance and repair difficulty. That’s important because you will be working on this car yourself if you want to keep your savings account intact. Besides, unlike the V12, you can get a straight-six with a manual transmission. And since all automatic XJS Jaguars are equipped with a rather sluggish and unreliable three-speed gearbox, a manual is the right way to go.

Besides, the V12 isn’t much faster anyway. For example, the early 5.3l Jaguar XJS V12’s top speed is 146mph, compared to the manual straight-six’s 144mph. Still, post-1994 V12 models are where you want to be. After that year, V12 engines grew to 6.0l and got 40hp more. That extra power and torque, combined with a four-speed auto transmission, brings you a 162mph top speed and shaves two seconds from the 0-60 time.

That being said, the straight-six engine isn’t more reliable than the V12, but it’s much easier to work on and much cheaper to maintain in the long run. Nonetheless, whichever engine you settle for, it should be 1994 and after. Not only is the V12 more powerful and gets a better transmission, but both engines have coil-on-plug ignitions, significantly increasing fuel efficiency, although not making them more reliable. Still, post-1994 engines don’t have as many head gasket issues, which is definitely a must.

Jaguar XJS Facelift vs. Pre-Facelift

The XJS saw three generations in its 22-year production span. The differences between the first two generations, 1975-1981 and 1981-1991 HE, are minimal. The only distinction is that the straight-six and manual transmission were introduced with the HE, and that’s pretty much it. But then came the facelift in 1991, bringing a modernized exterior with plastic bumpers and, later, updated taillights.

The facelift model was still undeniably an XJS, and it’s hard to spot the differences for someone that’s not an enthusiast or an owner. Ultimately, which design you prefer is totally up to you, but there are some key differences hiding behind the curtains you might want to consider. Namely, the galvanized body panels of the facelift XJS.

Indeed, the facelift XJS had a much simpler body, losing many of the smaller components, creases, and tunnels, reducing rust issues. Then, Jaguar galvanized all the major body parts, including the doors, the floor, and the rocker panels. Unfortunately, that didn’t solve the Jaguar XJS rust problem entirely. And, of course, you can find pre-facelift models with next to no rust. Still, to minimize the risk of corrosion, look for a facelift XJS and make sure to do a thorough rust inspection.

Jaguar XJS Common Problems

Whether you are buying a well-maintained XJS or one in poor condition, it’s good to know all its common problems in advance. That way, you know what to expect and what to pay close attention to. And even if it’s in good condition, preventive maintenance will go a long way with these cars, as XJS are not without regular problems.

Luckily, some of these issues are quite easy to fix, but you’ll have a hard time repairing serious ones without a Jaguar XJS service manual. Don’t know where to find one? Check — I get my repair manuals from there on the cheap, and they pay off for themselves after the first oil change.

With that said, here is what you can expect during your ownership.

List of Common Problems:

  • Corrosion on all body panels and floor
  • Oil leaks from the rear main oil seal
  • Interior water leaks through exterior mirrors, clogged drain pipes, and the AC system
  • Premature timing chain failure
  • Overheating because of a blocked radiator
  • Head gasket issues on all engines
  • Automatic transmission mounts coming loose
  • Distributor failure
  • Engine wiring melting between cylinder banks

Last Words

Unfortunately, the Jaguar XJS is one of the least reliable classic cars out there. Of course, some owners will still say their XJS has been reliable, but they would also probably admit that it cost them a fortune to keep it that way. So, if you are looking for a cheap sub $10,000 classic coupe, it’s best to stay away from this one — and if you can spend a bit more, you are much better off with an XK8.

Still, the XK8 has a different appeal as it looks much more modern. Hence, if you really want the elegant design of the Jaguar XJS, break out the tools, get your hands on a Jaguar XJS workshop manual, and say goodbye to most of your weekends. Otherwise, this car could very well mean financial ruin if you solely rely on the dealer to keep it running.