Magazine Cover - Classic Cars For Sale - 1000s of Classic Car Reviews, How To Service & Maintenance Guides

Jaguar XJ6 S1

Hit For Six Published: 5th May 2011 - 0 Comments - Be the first, contribute now!

Jaguar XJ6 S1

Fast Facts

  • Best model: 4.2 MOD
  • Worst model: 2.8 Auto
  • Budget buy: Daimler versions
  • OK for unleaded?: Yes
  • Will it fit in the garage? (mm): (mm): 4815 x 1770 x 1350
  • Spares situation: Very good
  • Club support: Good
  • Appreciating asset?: Slowly but surely
  • Good buy or good-bye?: Good buy
XK engine is robust; listen for rattly timing chains and over-silent tappet, latter meaning a head off job XK engine is robust; listen for rattly timing chains and over-silent tappet, latter meaning a head off job
4.2 engine viewed best all rounder; 2.8 burns pistons while 3.4 not much quicker. 4.2 engine viewed best all rounder; 2.8 burns pistons while 3.4 not much quicker.
Still a great looker but many won’t be in such good nick as rust is fi fe and so many cars are bodged due to their lowly values Still a great looker but many won’t be in such good nick as rust is fi fe and so many cars are bodged due to their lowly values
A lovely place to be but stamina is suspect. Look for ruined wood trim, rotten door cards and sagged, shot headlining A lovely place to be but stamina is suspect. Look for ruined wood trim, rotten door cards and sagged, shot headlining
XJs need the right tyres – cheap bodge was to fi t van tyres which ruined the handling and ride. Check their quality XJs need the right tyres – cheap bodge was to fi t van tyres which ruined the handling and ride. Check their quality
Magazine Subscription
The latest issue of Classic Cars For Sale is on sale now - Pick up your copy from all good newsagents including WHSmith or click here to subscribe now

Subscribe to Classic Motoring Magazine and save over 20%

Subscribe NOW

Available at all good newsagents including WHSmith

Jaguar’s XJ6 has just hit 40… and life looks great for those after a more refi ned and better value alternative to the Mk2!

Pros & Cons

Style, driving qualities, refi nement, value for money
Many ratty ones around, thirsty V12, slow to gain classic status
£500 – £10,000

Forty years on and arguably the XJ6 was the last true world-beating saloon to roll out of Browns Lane. When it fi nally surfaced in 1968 it broke the mould for prestige saloons, not just matching its class peers but redefi ning the sector altogether – a feat even the latest all aluminum XJ and the excellent XF have failed to copy. Using special low profi le Dunlop radials, you can even argue that the XJ6 was the last true ‘all new’ model from Jaguar - if you overlook the fact that the well evolved XK engine was by then 20 years old, and the suspension set-up had been refi ned through its bulky predecessor, the Mk X/420G. That’s stuff to debate down the pub… what isn’t in question is that the XJ is still an amazingly modern and competent luxury sports saloon that – when compared to Mk1/Mk2s–represents astonishing value for money. Just like it did back in 1968!


Demand was so great, that used prices outstripped new

The XJ6 wasn’t simply a new model for Jaguar, it redefi ned the company’s marketing strategy for the next 40 years. Boss Sir William Lyons decided that his range of saloons (Mk2, V8250 Daimler, S-Type/420, Mk10) was too overlapping and just one car should do it, leaving the sports stuff to the E-type. The XJ6 replaced everything before it and while it seemed a good idea at the time, history shows that it was a massive mistake, allowing the likes of BMW, Mercedes, Audi et al to steal sectors of the market Jaguar had dominated and reducing the company to nothing more than a bit part player over the next four decades. Also the new square cut lines, which were a world away from the curvaceous Jaguar saloons of the past and bang up to date (and when did you last say that about a Jag’s looks?) dictated the looks for all future Jag saloons since – again not a smart move. Still hindsight is a virtue and back in ’68 the XJ6 was the greatest thing since sliced bread. Developed during Jaguar’s heyday of the 1960s, the XJ was a no-compromise car that rewrote the handling and ride rulebook while taking refi nement to new levels. The 4.2-litre XK was joined by a new downsized 2.8, the latter mainly for certain European markets. Most came with a Borg Warner three-speed automatic, although some were specifi ed with a four-speed manual ’box, most of which came with overdrive. The by then legendary independent rear suspension set-up (introduced back in 1961 with the E-type and Mk X) together with coil springs, wishbones and anti-roll bar at the front gave the XJ its often-quoted ‘magic carpet’ ride. Brakes are, on the whole, the same as those that featured in its predecessor: three-pot calipers at the front surrounding solid discs, with inboard rear brakes. Power-assisted rack and pinion steering was standard.

Rightly so, demand was huge and there was initially a lengthy waiting list to be one of the fi rst behind the wheel meaning used XJs were selling over list price – by as much as a 50 per cent more! It all sounded great for Jaguar even if it was merged into British Motor Holdings (British Leyland) by now. But subsequent investment starved from the company, plus a troubled world economy in the 1970s, meant that Jaguar never carried on the momentum of this success. The XJ ultimately had to soldier on, albeit assisted by two major facelifts, until 1986, nearly 20 years after it originally appeared; by which point its classleading status had long since been usurped by German opposition. Even then, the V12 carried on alongside the replacement XJ40 until 1992! Posher Daimler versions were introduced in 1969, while, in 1972, a 5.3-litre V12 joined the range as did the option of a long-wheelbase model to counter criticisms of mediocre rear seat room, and a Rolls beating Vanden Plas Double Six. Still a sensational car, the Series 2 arrived in mid 1973, but many reckon this was the start of the slippery slide. The Series 2 differed little from the original, chief difference being at the front end, where a revised bumper height (demanded by US federal legislation), shallower grille and indicator lights now below the new bumper altered the XJ’s face noticeably. A new rear bumper comple mented the changes at the front, but the overall svelte silhouette of the original was retained. Technically, the S2 now boasted four-pot calipers and vented discs up front, while the auto box was now the swankier, smoother Borg Warner Model 65. There were minor tweaks to the interior with illuminated switchgear and climate control making their debut. At the same time a coupe derivative was announced, even though it wasn’t available until a year later. Also by the end of 1974, the long-wheelbase version became the standard model, as the short-wheelbase was discontinued. A 3.4 straight six replaced the tame, piston-burning 2.8 in 1975. The V12 models had their fi nal drive ratio altered in 1975 for more refi ned top-end cruising, while fuel injection also made its appearance on these big-engined versions following its introduction in the XJ-S (the UK six cylinders soldiered on with twin SU carburettors until the Series 3 came in 1979). From 1977 a GM three-speed automatic gearbox was employed in the V12 as it could better handle the massive amounts of torque.

Sadly around the mid 1970s Jaguar’s build quality was slipping, just as rivals were catching up. Yet despite this being a troubled period for Jaguar, over 225,000 Series 1 and 2 models were produced between 1968 and 1979. And while build quality and rust-proofing left a lot to be desired and arguably damaged Jaguar’s reputation for the next 30 years, enough have survived in the hands of caring owners for there to be plenty of them around today.

By rights XJ40 should have replaced S2 by now, having been in development since 1972. But it wasn’t even nearly ready (came out in ’86!) so the quick fi x was another makeover, in the shape of the March 1979-launched Series 3. Italian styling house Pininfarina was involved in this £7m project and – apart from past styling concepts – it was the fi rst time that an outside company had touched a Lyons cat. Bumpers were squared off, tail lamps restyled and fuel injection adopted on the 4.2 sixes – V12s were already injected – whilst entry level 3.4s stuck with twin carbs but had a slick and sensible Rover SD1 fi ve-speed gearbox instead of the old overdrive transmissions. There were careful suspension and running gear upgrades, the interior was subtly upgraded and the roof, quite literally, raised. Lack of rear headroom had bedeviled the car, so a restyled glasshouse and taller profi le were conceived. Jaguar had a serious tilt at sorting out the build quality woes and demand – especially in America – shot to unprecedented levels. When the six cylinder cars gave way to the XJ40 in 1986 they were still riding high and many regard the S3 as the best XJ of them all.


A good XJ6 is a dream drive and that sense of occasion is as strong now as it was back in ‘68. Sadly a lot of old Jag saloons seldom receive the maintenance they deserve. Consequently, the majority around today won’t offer anywhere near the magical combination of a supple ride yet wellmannered cornering of original cars. That evergreen XK engine is a classic. Granted the 2.8 was no ball of fi re when new with 142bhp (0 60 around 12 seconds – slower for the auto), but it’s very smooth. There aren’t many left now anyway due to unreliability and the offer of scant economy gains over the larger XK engines. The 3.4 is a better pick; it’s not the old Mk2 unit, but a downsized 4.2 unit giving 160bhp although the lustier 245bhp 4.2 has always been the most popular pick care of its excellent, seamless performance. Road test fi gures at the time quoted GTi-like performance such as 120+ mph and 0-60 in 8.7secs (manual) and 10.1 (auto), not to mention under 10 seconds to zip from 30-70mph through the gears, although fuel economy rarely broke into the 20mpg bracket.

The V12s were Ferrari beaters (146mph and 0-60mph in 7.4 seconds according to Autocar) with sensational mid-range punch. Okay so less than 15mpg isn’t funny these days, but if you use the car like a classic, does it matter that much? The V12 is still revered and feared by people in equal measure. Some will be horrifi ed by the maintenance prospects, while others will simply revel in the mind-blowing performance on offer by this mammoth engine. Quite frankly, it offered super car saloon standards owf performance, at a time when supercharged XJRs were not even a glint in the eyes of Jaguar engineers! Manual ‘boxes can feel slightly notchy, but once accustomed are actually easy to use. The three-speed automatics slur their changes and at motorway speeds can feel like they need an extra cog. Indeed a popular upgrade is to bolt on a four-speed auto from the later XJ40 models (seek a specialist for this). XJs in later life were sometimes fi tted with the wrong tyres by owners (usually as a costsaving exercise). They should be on VR rated tread – 205/70VR-15 to be precise. By today’s standard they’re incredibly high profi le, but it was this specially designed Dunlop rubber that, in part, contributed to the car’s world beating ride and modern rubber can spoil this.

In its June 1969 road test Autocar said that the XJ6 was the “smoothest and quietest car it had ever driven in” while the handling was “if anything, better than the E-type”. In its conclusion Autocar remarked that if the car were double its £2639 price tag it would still be value, but noted the car even then needed stricter quality control. With more expensive fi ttings the road test said it would wipe up the quality car market. If only Jaguar had heeded the advice.


During 1976/77 the XJ12C competed in the prestigious Group 2 racing series and even now you see XJs on the club scene. So there’s scope for tuning, although you may not want to spoil the car’s character, especially the handling and ride. Indeed simply by thoroughly overhauling the suspension and brakes to ‘as new’ standards will bring a dramatic change that’s enough for many. However, harder dampers and springs plus the obligatory ‘poly bushing’ will tighten the chassis.

As the XJ uses superior three or four pot calipers (depending upon car), just better pads may suffice. The XK engine is well known of course and the usual tuning methods naturally apply; bring the 4.2 up to full fat E-type spec is a good start but there’s a lot more to be done, including taking the unit out to 4.5-litres. Specialist JD Classics of Essex also markets its own modern fuel injection set up for this that’s said to work wonders.

If you want, manual cars can be fi tted with the Rover-sourced SD1 ‘box although the old overdrive system is as good. Autos can be upgraded to the a longer-legged four-speed unit taken from the XK40; Graham Whitehouse Autos ( markets a kit to do this; it costs some £4500 although does retain the standard bellhousing for authenticity.


For some strange reason prices have yet to rise to classic Mk2 levels, but many Jag experts see a change in the air. It’s reckoned that the S1s will be the most coveted and you can’t go wrong with a Sovereign spec 4.2, as this is undoubtedly the most desirable. S3 are next to due to their better running gear; S2s seem to have a stigma about them because they signify BL involvement. Coupe desirability seems to fl uctuate and good ones are not that plentiful in number. There’s not a huge difference between shortand long-wheelbase in terms of price, so just consider whether you need the extra 4in of legroom provided by the bigger model. Like a lot of Jag saloons, the real bargains can be found with those sporting the dignifi ed Daimler badge. Usually they’re cheaper than the equivalent XJ, yet with a marginally higher spec.

While there will be basket XJs out there for £500, we’d say a more realistic starting point is double that. One can start getting a bit picky around the £4000 mark, with £5000 representing the ideal price, certainly for a private sale. Forecourt cars and particularly mint Series 1s can fetch more, while coupes should only really be considered from around the £4500 mark for fear of buying a partial restoration project or a complete shed.

What To Look For

  • As with any classic from this era, rust will be an ever-present threat. So try and look past a fresh coat of polish and delve deeper. XJs tendto sport bubbles round the top of the headlights, lower front wings, doors on the edge which meets the front wing and where it meets the sill; the rear wheel-arch and screen surrounds.
  • But that’s just the obvious areas – there’s still more probing to do! Ideally, get the car off the ground for a nose underneath, checking the lower front valance and cross-member below the radiator, while the rear valance comprising of the spare wheel well is another harbour of iron oxide.
  • Open the bonnet and while checking the engine, also observe the leading edge of the bonnet where the hinges are, the inner wings and suspension turrets.
  • The valance panels are known rot areas, especially the rear around the twin exhausts. These are often full of fi ller – S1 and S2s seem to suffer the most. At the from check the crossmember under the rad carefully as it is structural.
  • Watch for milkiness in the windscreen corners. S3 screens were bonded in, and with time condensation works its way between glass and metal, oxidising the windscreen pillars, sometimes with terminal results. Bulkhead rot can be a problem too, and it’s diffi cult to spot, particularly with V12s.
  • Oil pressure should be around 40lb.ft at cruising speeds and there should be no knocking or rumbling under load. V12s run at 45-55lb.ft if good and this engine is virtually impossible to wear out.
  • XK watch points include over silent tappets (meaning a head off decoke and re-shim job), noisy timing chains (the bottom one is a pig to replace by the kerb) and leaking rear crankshaft oil seals, which given the complete strip down of the unit, may be best left alone unless really bad.
  • Carbs on the XK were SUs, but 4.2 S3s feature fuel injection and the infamous Lucas Opus (‘opeless) electronic ignition. The former is a fairly simple set up that’s reliable while the latter is best swapped for a modern upgrade! In Series 3 guise the XJ joined the computer age with a boot mounted ECU, so it’s important that all the electrical bits work as Jaguar intended – and many don’t.
  • The Salisbury rear axle is sturdy enough, but it can seep oil round the pinion seal. Leaks emanating from the driveshaft seals should be viewed seriously as the escaping oil can contaminate the inboard rear brake discs.
  • That much-heralded independent rear suspension needs to be dropped to gain access to the rear brakes, so consider this when reviewing any necessary work at the back. If the rear suspension is looking a tired, consider changing the brakes at the same time, as this will save a lengthy job later on.
  • Obvious checks to the suspension comprise simply walking round the car to see if it sits fl at and square – there should be no sagging springs – while assessing any uneven tyre wear will also indicate any problems.
  • The handbrake has it’s own, rather feeble little pads and calipers, tucked completely out of sight. These are awful to work on, hard to set up and a common MOT failure point.
  • Rubber is the thing that made the XJ6 ride so well. Renewing this little lot will transform the way the car drives back to the way it would have done when new. Floaty steering will probably be down to rack bushes while a clonking noise is typically universal joints past their prime.



Three Of A Kind

BMW 7 Series
BMW 7 Series
The E23 7 Series ran from 1977 to ’86 and wooed a lot of dissatisfi ed Jag owners to the German badge, not simply due to better reliability but also a wider engine line up. A sportier choice than the Jaguar but a car which requires a lot more skill in the wet due to a skittish tail, the BMW is still grossly overlooked in classic circles. Later 7 Series used more electronics and these can give expensive trouble.
Mercedes W123/4
Mercedes W123/4
A smaller car than the XJ but one which matched it for price, the Mercedes sacrifi ces sportiness and serenity for stamina and they make dependable daily drivers with a wide engine choice to suit all pockets. There’s also the benefi t of estate and coupe models. W123 range ran from 1976 to ‘85, replaced by smoother W124 but all are built to last in a way Merc don’t make them anymore. Parts supply from the factory is still excellent.
Replacement for the XJ is arguably an even better drive that’s still well up to modern standards with punchier engines that are far more frugal. Early build glitches sullied the car and they still languish as banger buys but these Jags will have their day in the sun. Lots around, so be very choosy; 3.6 and 4.0 cars best, but all rust badly and head gasket, timing gear and rear suspension woes fairly common.


The XJ is a genuine landmark car for Jaguar and remains so to this day. They are a much better car than the Mk2 or S-Type and yet values have yet to refl ect this. However, this can’t remain and now’s one of the best times to buy what was described in its day as the best car in the world.

Share This Article

Share with Facebook Share with Facebook

Share with Twitter Tweet this article

Share bookmark with Delicious Share bookmark with Delicious

Share with Digg Digg this article

Share with Email Share by email

User Comments

This review has 0 comments - Be the first!

Leave a comment

Keep it polite and on topic. Your email address will not be published. Please do not advertise products, all posts of this nature will be removed. We do not stock or supply any of these products, we independently review these products.

Subscribe Today
Latest Issue Cover - Click here to subscribe

Subscribe to Classic Motoring Magazine and save over 25%