The Jaguar XJ is a series of mid-size/full-size luxury cars produced by British automobile manufacturer Jaguar Cars (becoming Jaguar Land Rover in 2013) from 1968 to 2019. It was produced across four basic platform generations (debuting in 1968, 1986, 2003, and 2009) with various updated derivatives of each. From 1970, it was Jaguar's flagship four-door model. The original model was the last Jaguar saloon to have been designed under the leadership of Sir William Lyons, the company's founder, and the model has been featured in a myriad of media and high-profile appearances.
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Series 1, 2, and 3 (1968–1992)
The first generation Jaguar XJ was produced for a total period of 24 years, with two major facelifts – in 1973 and in 1979, with a raised front bumper and less tall grilles.
For four years, the 1968 introduced XJ (later known as the Series 1) was a four-door, straight-six saloon on a wheelbase. In 1972, a more spacious, longer wheelbase (LWB) option, and a 5.3 litre V12 engine were added. On the XJ series 2 (from 1973), the standard wheelbase (SWB) saloons were cancelled in 1974 – but a SWB two-door (series II only) coupé was sold from 1975–1978.
The 1979 series 3 saloons received a redesigned greenhouse (upper body) and bumpers. The 6-cylinder series 3 models were replaced by the second generation Jaguar XJ in 1987, but the V12 models were not replaced until 1992.
Series 1 (1968–1973)
The XJ6 replaced most of Jaguar's saloons – which, in the 1960s, had expanded to four separate ranges. It carried over the 2.8-litre () and 4.2-litre () cylinder versions of Jaguar's renowned straight-six XK engine, and front and rear suspensions, from previous models: the widest version of Jaguar's IRS unit from the Mark X, and the subframe-mounted independent front suspension first seen in the 1955 Mark 1, with new anti-dive geometry.
left|thumb|Series 1 Jaguar XJ6 rear
left|thumb|Series 1 Jaguar XJ6 interior
An upmarket version was marketed as the Daimler Sovereign, continuing the name from the Daimler version of the Jaguar 420. The car was introduced in September 1968. Power-assisted steering and leather upholstery were standard on the 2.8 L De Luxe and 4.2 L models. Air conditioning was offered as an optional extra on the 4.2 L Daimler versions, which were launched in October 1969 in a series of television advertisements featuring Sir William. In these advertisements, he referred to the car as "the finest Jaguar ever". An unusual feature inherited from the Mark X and S-Type saloons was the twin fuel tanks, positioned on each side of the boot, and filled using two separately lockable filler caps: one on the top of each wing above the rear wheel arches. Preliminary reviews of the car were favourable, noting the effective brakes and good ride quality.
In March 1970, it was announced that the Borg-Warner Model 8 automatic transmission, which the XJ6 had featured since 1968, would be replaced on the 4.2-litre XJ6 with the Borg-Warner Model 12. The new transmission had three different forward positions accessed via the selector lever, which effectively enabled performance oriented drivers to hold lower ratios at higher revs to achieve better acceleration. Bonnet louvres such as those fitted on the 12-cylinder E-Type were rejected and instead the XJ12 featured a complex "cross-flow" radiator divided into two separated horizontal sections supported with coolant feeder tanks at each end. The engine fan was geared to rotate at 1¼ times the speed of the engine, subject to a limiter which cut in at a fan speed of 1,700 rpm. reviving the Daimler model name of 1926–1938.
{| class="wikitable"
|+ Total production figures for the Series 1
|-
! Model
! Production
|-
| Jaguar XJ6 2.8 swb
|align="right"| 19,322
|-
| Jaguar XJ6 4.2 swb
|align="right"| 59,077
|-
| Jaguar XJ6 4.2 lwb
|align="right"| 574
|-
| Jaguar XJ12 swb
|align="right"| 2,474
|-
| Jaguar XJ12 lwb
|align="right"| 754
|-
| Daimler Sovereign 2.8
|align="right"| 3,233
|-
| Daimler Sovereign 4.2 swb
|align="right"| 11,522
|-
| Daimler Sovereign 4.2 lwb
|align="right"| 386
|-
| Daimler Double Six swb
|align="right"| 534
|-
| Daimler Double Six Vanden Plas
|align="right"| 351
|- style="font-weight:bold"
| Total Production for Series 1
| style="text-align:right;"| 98,227
|}
Series 2 (1973–1979)
The XJ line received a facelift in Autumn 1973 for the 1974 model year, thereafter known as the Series II; retrospectively the earlier cars were referred to as the Series I. The 4.2 L XJ6 straight-6 engine (most popular in the United Kingdom) and the 5.3 L V12 XJ12 were continued with an addition of a version of the XK engine available from 1975. The Series II and Series II coupé were the last Jaguar models with direct input by Sir William Lyons before his retirement.
Initially, the Series II was offered with two wheelbases, but at the 1974 London Motor Show Jaguar announced the withdrawal of the standard wheelbase version: subsequent saloons all featured the extra 4 inches (10 cm) of passenger cabin length hitherto featured only on the long-wheelbase model. By this time, the first customer deliveries of the two-door coupe, which retained the shorter standard-wheelbase (and which had already been formally launched more than a year earlier) were only months away.
Series II cars are visually differentiated from their predecessors by raised front bumpers to meet US crash safety regulations, which necessitated a smaller grille, complemented by a discreet additional inlet directly below the bumper. The interior received a substantial update, including simplified heating and A/C systems to address criticisms of the complex and not very effective Series I systems.
In April 1975, the North American models got a slightly revised set of front bumpers which had rubber over-riders covering the full length of the bumper with embedded turn signals at each end, and the Zenith-Stromberg carburettors of the V12-powered cars were replaced by Bosch-Lucas electronic fuel injection. In 1978 the carburettors were similarly replaced with EFI in the 4.2 L 6-cylinder XJ6L. In May 1977, it was announced that the 12-cylinder engine would receive the General Motors' three-speed Turbo-Hydramatic 400 automatic transmission in place of the British-built Borg-Warner.
The 1978 UK model range included the Jaguar XJ 3.4, XJ 4.2, XJ 5.3, Daimler Sovereign 4.2, Double-Six 5.3, Daimler Vanden Plas 4.2 and Double-Six Vanden Plas 5.3. In New Zealand, knock-down kits of the Series II were assembled locally by the New Zealand Motor Corporation (NZMC) at their Nelson plant. In the last year of production in New Zealand (1978), a special 'SuperJag' (XJ6-SLE) model was produced which featured half leather, half dralon wide pleat seats, vinyl roof, chrome steel wheels and air conditioning as standard. New Zealand produced models featured speedometers in km/h, and the black vinyl mats sewn onto the carpets in the front footwells featured the British Leyland L logo.
Though worldwide production of the Series II ended in 1979, a number were produced in Cape Town, South Africa until 1981. A total of 91,227 Series II models were produced, of which 14,226 were fitted with the V12 engine.
Engines
{| class="wikitable"
|-
! Years
! Type
! Capacity
! Horsepower
|-
| 1973–1975
| DOHC I-6
| 2,792 (171 cu. in.)
| 140 Cv/Din
|-
| 1975–1979
| DOHC I-6
| 3,442 (210 cu. in.)
| 160 Cv/Din
|-
| 1973–1979
| DOHC I-6
| 4,235 (258 cu. in.)
| 186 Cv/Din - 172 Cv/Din <sub>See Note</sub>
|-
| 1973–1979
| SOHC V12
| 5,343 (326 cu. in.)
| 269 Cv/Din <sub>See Note</sub>
|}
Note that HP varies depending on emission standards imposed on particular vehicles
Production count
{| class="wikitable"
|-
! Model
! Swb
! Lwb
|-
| Jaguar XJ6 3.4
| —
| 6,490
|-
| Jaguar XJ6 4.2
| 12,370
| 50,912
|-
| Jaguar XJ12 5.3
| —
| 14,226
|-
! Total
! 12,370
! 71,628
|}