The Jaguar XJ6 Story

Origins

By the mid-1960s, Jaguar’s saloon car range was a mess. Three separate models, the compact Mark 2, the large Mark X (later 420G), and the S-Type (a Mark 2 with an independent rear end grafted on), covered the same territory with different platforms, different bodies, and different production lines. It was inefficient, confusing, and unsustainable. What Jaguar needed was a single new saloon that could replace the lot.

Sir William Lyons, Jaguar’s founder, chairman, and chief stylist, took personal charge of the project. The new car, coded XJ4 initially, then XJ6, would be his final masterwork. It had to be the best saloon car in the world. Not the fastest, not the most luxurious, not the most technologically advanced, simply the best, in the way that Lyons understood the word: a car that combined ride quality, refinement, performance, style, and value better than anything else on the road.

The development programme was extensive. Bob Knight, Jaguar’s chief engineer, led the chassis and suspension work with an obsessive focus on ride quality. The new independent rear suspension (an evolution of the E-Type’s system), double-wishbone front suspension, and sophisticated anti-dive/anti-squat geometry were developed over years of testing. Knight’s team spent countless hours on ride comfort, damper valving, spring rates, bush compliance, with the goal of creating a car that felt like it was floating over the road surface rather than driving on it.

The engine was the proven XK twin-cam six, offered in 2.8-litre and 4.2-litre forms. This was a conservative choice, the XK was already twenty years old, but it was reliable, well-understood, and still one of the smoothest six-cylinder engines in production. A V12 option was planned from the outset but wouldn’t be ready for launch.

The Launch

The XJ6 was unveiled on 26 September 1968, and the automotive world immediately recognised it for what it was: the best saloon car on the planet. The praise was universal and unequivocal. Every major motoring publication, Autocar, Motor, Car and Driver, Road & Track, concluded that the XJ6 set a new standard for ride quality, refinement, and handling in a luxury saloon.

This wasn’t faint praise. The XJ6 was being measured against the Mercedes-Benz W108 S-Class and the BMW 2500, the established benchmarks of the luxury saloon market. And it beat them both. The ride quality was in a different league, smoother, more composed, more cosseting than anything from Stuttgart or Munich. The handling, despite the emphasis on comfort, was genuinely sporting, the XJ6 cornered with a precision that belied its size. And the performance was strong: the 4.2 managed 0-100 km/h in around 8.5 seconds and a top speed of 195 km/h.

All of this for significantly less money than a comparable Mercedes or BMW. Lyons’s lifelong formula, offering more car for less money than the competition, reached its zenith with the XJ6.

The styling was Lyons at his finest. The XJ6 is a low, wide, flowing shape with a roofline that sits remarkably close to the ground for a full-sized saloon. Slim pillars, generous glass area, subtle curves, and restrained chrome create a car that manages to look both imposing and elegant simultaneously. Lyons obsessed over the proportions, the relationship between the roofline and the waistline, the stance, the way the light played across the flanks. The result is arguably the most beautiful saloon car ever designed.

Series 1 Production (1968-1973)

The Series 1 XJ6 was offered in standard and long-wheelbase (LWB) forms, with 2.8-litre or 4.2-litre engines. The LWB added 100mm to the rear door aperture and rear legroom, it was intended primarily for chauffeur-driven use and Daimler-badged models.

The Daimler Sovereign was the luxury derivative, the same car mechanically, but with the distinctive fluted Daimler grille, Daimler badges, and higher trim levels. The practice of offering Jaguar and Daimler versions of the same car would continue throughout the XJ6’s life, adding a layer of confusion that the marketing department seemed to relish and customers mostly ignored.

The 2.8-litre engine was a mistake. De-stroked from the 4.2 to create a lower-cost entry point, it was rough, underpowered, and prone to overheating and bearing problems. Very few were sold in Australia, and those that were have largely been converted to 4.2 specification or scrapped. If you encounter a 2.8, the correct response is to buy a 4.2 instead.

In 1972, the V12 arrived, first as the XJ12 (Jaguar) and then as the Daimler Double Six. The 5.3-litre single-overhead-cam V12, already proven in the Series 3 E-Type, turned the XJ into the world’s first V12 production saloon. The refinement was extraordinary, at idle, you could balance a coin on the engine and it wouldn’t fall off. At motorway speed, the V12 XJ was one of the most civilised machines on the road.

It was also spectacularly thirsty. Fuel consumption of 20-25 L/100km was standard, which became a significant problem when the oil crisis hit in 1973. The V12 would remain available throughout the XJ6’s life, but it was always a minority choice, a statement of engineering capability rather than a practical proposition.

The British Leyland Years and Series 2 (1973-1979)

Jaguar had been absorbed into British Leyland in 1968, and the consequences were becoming apparent by the early 1970s. Industrial disputes, management upheaval, and chronic underinvestment affected quality and productivity. The XJ6’s build quality, which had been excellent at launch, deteriorated. Paint quality suffered. Panel fit worsened. Electrical gremlins multiplied.

The Series 2, introduced in 1973, was primarily a response to US safety regulations. The bumpers grew larger and heavier (raised rubber-faced units that added weight and reduced visual elegance). The grille was enlarged. The interior was modified to meet impact regulations. Smaller changes included revised air conditioning, improved heating and ventilation, and detail updates throughout.

Mechanically, the Series 2 was progressively improved. Fuel injection appeared on some markets (Lucas systems, not always successfully). The power steering was refined. The suspension was tuned. But the overall impression was of a car struggling under the weight of regulation and corporate dysfunction.

Build quality reached its nadir in the mid-1970s. Cars left the Brown’s Lane factory with misaligned panels, paint defects, water leaks, and electrical faults. Jaguar’s reputation, carefully built over decades, suffered badly. In Australia, the dealer network struggled to maintain customer confidence in the face of persistent quality complaints.

Despite all this, the Series 2 XJ6 remained a fundamentally excellent car. The ride quality was still supreme. The 4.2 XK engine was still smooth and willing. The handling was still better than the competition. You just had to look past the build quality to appreciate it, a harder ask than it should have been.

The Pininfarina Facelift: Series 3 (1979-1992)

The Series 3 represented a turning point for Jaguar. The decision to engage Pininfarina, the Italian design house responsible for some of Ferrari’s most beautiful cars, to update the XJ6 was initially controversial within Jaguar. Lyons had retired by this point (he died in 1985), and the idea of an Italian styling house touching a Jaguar was seen by some as a betrayal.

The result silenced the critics. Pininfarina’s changes were subtle but effective: a slightly raised roofline improving rear headroom, flush-fitting door handles replacing the chrome pull types, revised bumpers with a more integrated appearance, and cleaner detailing throughout. The essential Lyons proportions were preserved, Pininfarina understood that the XJ6’s shape was too good to reinvent, only to refine.

The Series 3 launched in 1979 and would remain in production until 1992, an extraordinary 13-year run that speaks to the fundamental rightness of the design. During that period, the car was continuously improved. Build quality rose steadily, particularly after John Egan’s arrival as chairman in 1980. Egan transformed Jaguar’s manufacturing culture, addressing the quality problems that had plagued the brand throughout the 1970s.

Key improvements during the Series 3 run included the switch from Lucas to Bosch ignition (a transformative change in reliability), improved corrosion protection, better trim materials, and progressive refinement of every system. Late-production Series 3 cars, from roughly 1987 onwards, are the best of the breed: well-built, well-equipped, and with most of the earlier car’s weaknesses addressed.

The Sovereign name became the premium trim level for Jaguar-badged cars, offering leather, wood, electric seats, climate control, and comprehensive equipment. The Daimler versions continued with their fluted grilles and higher-spec interiors. Both used the same mechanicals.

The V12 in the XJ

Throughout all three series, the V12 option offered an alternative experience. Where the 4.2 six was refined and willing, the V12 was supernaturally smooth and effortlessly powerful. The V12 XJ, whether badged as XJ12, Sovereign V12, or Daimler Double Six, was the ultimate expression of the concept: a luxury saloon with the engine of a supercar, wrapped in a package that valued serenity above all else.

The V12 was progressively developed: the HE (High Efficiency) version arrived in 1981 with drastically improved fuel economy (from ruinous to merely excessive), and the 6.0-litre version in the final XJ12 models offered even more torque and refinement.

But the V12 was always a niche choice. The fuel consumption, maintenance complexity, and higher running costs limited its appeal to enthusiasts and the genuinely wealthy. For most XJ buyers, the 4.2 six was more than adequate, and that’s the engine that defines the model.

In Australia

The XJ6 was imported into Australia from launch, initially through Brysons and later through Jaguar’s own distribution network. It found a receptive market, Australia’s appreciation for British luxury cars was strong, and the XJ6 offered more sophistication than anything locally produced.

Most Australian-delivered XJ6s were 4.2-litre automatics with Sovereign or Daimler trim. The V12 variants were sold in smaller numbers, fuel cost consciousness was real even before the oil crisis. Right-hand drive was standard, and Australian-specification cars received air conditioning and other warm-climate adaptations.

The Australian climate was generally kind to XJ6 bodywork, drier conditions and no road salt meant less rust than equivalent British or European cars. But Sydney’s coastal humidity, Melbourne’s rain, and the general tendency of all steel cars to rust eventually meant that even Australian XJ6s weren’t immune. Neglect, blocked drains, failed seals, cars sitting unused, caused the same damage regardless of latitude.

The JDCA played a crucial role in supporting XJ6 owners through the car’s life and beyond. State branches maintained service registers, organised technical days, and built the knowledge networks that made ongoing ownership practical. The club’s XJ registers remain active and are invaluable resources for prospective buyers, they can trace an Australian-delivered car’s history and connect you with specialists who know these cars intimately.

Australian XJ6 specialists exist in every major city. The XK engine’s widespread use across the Jaguar range (E-Type, XJ-S, XJ6) means mechanical parts are readily available and well-understood. Body panels and trim are sourced primarily from UK specialists (SNG Barratt, David Manners) who ship to Australia routinely.

Today, the XJ6 occupies an interesting position in the Australian classic car market. Series 3 models, in particular, represent extraordinary value, a well-presented Jaguar luxury saloon for the price of a forgettable used car. The appreciation for the car’s qualities is growing as enthusiasts recognise that the ride, refinement, and character on offer are simply not available in anything else at the price.

Legacy

The XJ6 defined the luxury saloon for a generation. When Mercedes-Benz developed the W116 S-Class (launched 1972), the XJ6 was the benchmark they were trying to beat. When BMW developed the E23 7 Series (launched 1977), the same was true. The XJ6 set the standard that everyone else worked to meet, and for many years, nobody quite did.

Lyons’s achievement with the XJ6 was remarkable in its completeness. The car wasn’t just good at one thing, it excelled at everything. Ride quality, handling, refinement, performance, style, value, the XJ6 led or matched the class in every metric. This comprehensive excellence is what makes it one of the great cars of the twentieth century, rather than merely a good one.

The XJ platform continued in evolved form as the XJ40 (launched 1986, replacing the six-cylinder XJ6) and various subsequent iterations through to the aluminium XJ of 2003. But none of the successors quite matched the original’s magic. The Series 1 and Series 3, in particular, have a quality that later cars, for all their objective improvements, struggle to replicate: a sense of occasion, a rightness of proportion, a feeling that every element of the car was designed by people who cared deeply about the result.

Park a Series 1 XJ6 next to a current luxury saloon. The modern car is better in every measurable way, faster, safer, more efficient, more reliable. But the Jaguar has something the modern car doesn’t: soul. That ineffable quality that makes you want to go for a drive even when you don’t need to go anywhere. The XJ6 has it in abundance, and that’s why, fifty-plus years after its debut, people still fall in love with it.