Buying Guide Jaguar XJ6 Series 3


The XJ range was already well over ten years old by the time the Series III was officially launched in March 1979, successfully updating an elderly design by giving it some ’80s-style tweaks. It was a thorough job, of course, with a new grille and more modern bumpers once again leading the way, along with minor trim changes like flush-fitting door handles. But the biggest styling upgrade was at the rear, where the roofline was raised and squared off for a surprisingly different – but rather attractive – new look.

In side profile, the difference between the Series III and its Series II predecessor was immediately noticeable and rather pleasing; rear seat passengers also benefited, thanks to the extra rear headroom provided by this Pininfarina-penned restyle. It might have been getting on in years but the XJ range was about to enjoy a whole new lease of life.

By the early ’80s (and under the control of Sir John Egan), Jaguar was also making great improvements when it came to the quality of its cars. Indeed, by the time Jaguar was floated off as a separate company in 1984 (after many years shackled to what had once been the British Leyland empire), the entire line-up was noticeably improved in terms of build quality and reliability, benefiting Jaguar greatly both in the UK and in the company’s crucial export markets around the world.


As before, the latest XJ6 range provided a choice of 3.4- and 4.2-litre members of the XK six-cylinder family, with the 5.3-litre V12 inevitably appearing in the XJ12. As we’ve covered the Series III XJ12 in a previous issue, however, we’re focusing on the six-cylinder models here.

The full range at the start of the XJ6 Series III’s career kicked off with the 3.4- and 4.2-litre models, priced at £13,259 and £14,809 respectively by the end of 1979. Buyers wanting the ultimate in XJ6-style luxury however, could upgrade to the Daimler 4.2 Sovereign and 4.2 Vanden Plas, listed at £15,387 and £20,384 respectively. That made the Vanden Plas roughly 40% dearer than the XJ6 with the same 4.2-litre engine, which inevitably meant far lower sales of the most expensive six-cylinder Daimler.

The end of the Series III XJ6’s career brought a little more choice, with the full range of Jaguar-badged six-cylinder models consisting of the XJ6 3.4 (£15,595), XJ6 4.2 (£16,995) and Sovereign 4.2 (£20,795) by early 1986. The only six-cylinder Daimler at that late stage was the 4.2, priced at £25,195.

Numerous changes were carried out during the eight-year career of the XJ6 Series III, including the renaming of the Daimler Sovereign (to Jaguar Sovereign) for the 1983 model year, plus more availability of the five-speed manual transmission option at the same time – although XJ6 buyers who didn’t crave an automatic were very much in the minority. The six-cylinder Series III models were wound down in Europe following the launch of the XJ40 in late 1986, yet they remained on sale in the USA well into ’1987 – with the final car being delivered in May of that year.

On today’s classic market, your final choice of Series III trim level and spec will depend as much on what’s available for your budget as on any personal preference. The Daimler derivatives inevitably offer the ultimate in opulence, but nobody could accuse any Series III XJ6 of lacking when it comes to luxury. Engine-wise, meanwhile, most enthusiasts agree that the 4.2-litre XK six-cylinder is the best of the bunch, offering a more effortless 205bhp to the 3.4’s 162bhp. In reality, however, any XJ6 will provide you with a smooth, refined and powerful enough driving experience.


Bodywork: For any buyer of a six-cylinder Series III (or any XJ6 for that matter), the most crucial area of concern is its bodywork, with its monocoque bodyshell being prone to rust in all the regular areas. When giving any Series III a good check-over, carefully inspect all structural areas for signs of corrosion and poor quality previous repairs – including both inner and outer sills, floorpans, all box sections and ‘chassis’ members, the front subframe and its mounts (although oil leaks from the engine often protect the front end) and – perhaps most importantly of all – the rear suspension mounting points. Repair sections and part-panels are available for the Series III, so make sure you’re checking for signs of any such work when carrying out your inspection. Also be on the look-out for non-original paintwork; an older restoration carried out to a high standard will cause few problems, but any fresh paint should arouse suspicion as it could be hiding an array of hastily-done repairs.

As well as checking all the usual rot spots, you should also be on the lookout for signs of bubbling around the XJ6’s front and rear screen surrounds, invariably caused by moisture trapped under the rubbers; it might not look severe, but such bubbling can be a sign of major rust beneath, which is obviously a screen-out job. This kind of problem can also cause leaks inside the car, which can lead to trim damage. If you do take on an XJ6 Series III in need of some work, you’ll obviously benefit from excellent parts availability, although you must research the costs involved before considering such a project. SC Parts will sell you a front wing for just over £1300, for example, while a complete rear wing will set you back £465-650 depending on which side you require. David Manners, meanwhile, stocks a range of repair sections and reproduction panels, including a complete rear valance (£54), front cross-members (£84), toeboards (£78), lower rear quarter panels (from £52) and floorpan repair sections (from less than £105).

Engine and transmission: The XK straight-six engine is a famously robust design that’s easily capable of high-mileage motoring when well maintained and regularly serviced. The majority of today’s Series IIIs will be well looked after, but that hasn’t always been the case; when these cars were at their ‘banger’ stage, the use of something as basic as a poor quality antifreeze could cause all sorts of problems.

The obvious advice, therefore, is to make sure any XJ6 you’re thinking of buying comes with proof of careful maintenance over the years; if there’s a lack of invoices, receipts or service history, you need to tread carefully.

Most 3.4- and 4.2-litre engines that haven’t been rebuilt in recent times will burn a little oil, but that’s not necessarily a sign of problems ahead. You should, however, listen for any obvious rattles from the timing chain (both at idle and as the revs rise), as it’s not unknown for chains to break; replacement is inevitably a major undertaking, so make sure you budget for this if you feel there’s a problem. Head gasket failure isn’t rare, so you also need to check for signs of coolant in the oil (and vice-versa).

Listen out for any bearing noise during the first few moments of starting the engine from cold, and check that the oil pressure is reading at least 40psi (at around 3000rpm) once it’s up to normal operating temperature. XJ6 oil pressure gauges weren’t always wholly accurate even when the Series III came along, but should provide a reasonable indication.

The Borg-Warner three-speed automatic transmission fitted to most Series IIIs is tough and reliable, although long-term maintenance (via fluid changes) is again the key to reliability. On your test drive, make sure that the gears change smoothly and without hesitation, and make sure the car doesn’t jump out of gear – particularly when under load. Manual versions of the Series III are fairly unusual, but the five-speed ’box they use is generally reliable; check for clutch slip when testing the car, as fitting a new clutch involves engine removal and is a labour-intensive job. Suspension, brakes and steering: The XJ6’s independent rear suspension and subframe are complex in design, featuring inboard rear brake discs.

It’s a highly effective system when working well, albeit not the simplest for any DIY-orientated owner to work on. There’s a multitude of rubber joints, mountings and universal joints under there too, with any major wear in these making themselves felt via a generally ‘tired’ feel out on the road. Parts prices are competitive, of course, with David Manners stocking rear springs and rear shock absorbers from less than £23 and £32 each respectively; you can pay more depending on the spec and/or level of originality you’re chasing, but it shows that shopping for spares needn’t be horribly expensive.

You should also listen out for clunking noises when pulling away, likely to be caused by wear in either the propshaft or half-shaft universal joint – although it’s not unknown for the subframe mountings (or even the radius arm mounts) to be pulling away from the back end of the floorpans on severely neglected cars. If you’re unsure what to look for, it’s best to get the car checked out by an expert.

When it comes to the brakes, check that the handbrake doesn’t need adjusting (it’s mounted up above the rear discs and is a tricky job), ask when the pads were last changed, and carry out the usual checks for fluid leaks, rusted brake pipes and so on; you also need to ensure that the diff hasn’t leaked oil on to the brake pads. The steering set-up is durable, though parts are generally inexpensive should anything go wrong; David Manners sells Series III steering rack seal kits from £42, as well as bush kits and gaiters for just over £13 and £5 respectively.

Interior, electrics and trim: The wood-and-leather interior of the Series III was, of course, one of its key attractions – but all these years later, it needs checking carefully for signs of potentially expensive problems. Indeed, the state of any XJ6’s interior is vital if you’re to avoid it quickly becoming a money pit. Check the leather upholstery for signs of cracks and splits (particularly the driver’s seat), and make sure that the carpets are intact and aren’t suffering from dampness. The veneer used on the dashboard and door cappings should be in good order and the lacquer should be crazefree, as a professional re-lacquering to original spec will be very expensive. You should also check the headlining for signs of sagging; and don’t forget to look in the boot for more signs of wear and dampness. Just as importantly, make sure everything electrical is working as it should; Jaguar reliability improved dramatically in the ’80s, but you should still ensure that the electric windows, central locking and all dials and switches are functioning as normal. If air conditioning is fitted, make sure this is blowing cold and check that the heater also works well.


One of the big attractions of the Series III (as with any other XJ6) is the cost of maintenance, as the vast majority of off-the-shelf service items are extremely affordable. We’ve already mentioned some of the prices you can expect, which means that – unless you’re deliberately taking on a project – your Series III shouldn’t be prohibitively expensive to maintain. Labour rates will vary (assuming you use professionals when it comes to maintenance and servicing), but the relatively straightforward spec of the XJ6 helps to ensure a sensible timescale when it comes to servicing. In terms of modifications, there’s not much that a well-preserved Series III requires by way of improvement thanks to the sheer competence of this final incarnation. For anyone looking for improved braking efficiency, however, Coopercraft (www.coopercraft. offers a choice of front brake kits, kicking off with the non-vented version (which comes with four-pot billet-aluminium calipers, stainless steel pistons and new pads), priced from £510. And if you’re in the market for a stainless steel exhaust, the two systems available from SC Parts (to fit 1979-81 and 1981-on Series IIIs) offer good value at just under £579.


There was a time when a Series III XJ6 could be picked up in good condition at a bargain price. Even as values of the Series I (and, a little later, the Series II) began to increase dramatically, the Series III was still seen by many as a less ‘classic’ option – hence prices that were substantially lower. These days, however, more than thirty years on from the last six-cylinder Series III being produced, this final version of the classic XJ is now more sought after.

“…there’s not much that a well-preserved Series III requires by way of improvement thanks to the sheer competence of this final incarnation”

The asking prices of decent survivors have certainly risen in recent years, although an immaculate Series III still offers better value than a Series I in the same condition. Project cars start from just a few hundred pounds (although we’d question the viability of buying such a down-at-heel example), while MoT’d but cosmetically poor Series IIIs can be found for £3000-3500. Tidy examples tend to start at around the £5000-6000 mark, though you’ll need £8000-plus for a low-mileage car that’s ready to show and enjoy – with the very best Series IIIs commanding asking prices of up to £15,000.

“The majority of today’s Series IIIs will be well looked after, but that hasn’t always been the case”



David Manners

Ken Jenkins –

SNG Barratt –

SC Parts –

Martin Robey


Jaguar Enthusiasts’ Club

Jaguar Drivers’ Club

“The Daimler derivatives inevitably offer the ultimate in opulence, but nobody could accuse any Series III XJ6 of lacking when it comes to luxury”

Tyre condition can be a clue to how well a car is cared for. 4.2- or 3.4-litre are the engine options.

XK engine robust, but doesn’t tolerate neglect. As we well know. See page 90. Arches and screen surrounds can corrode, but underside needs careful checking. A top-notch interior adds considerable value. Check seat bolsters and dashboard. The very last XJ6 Series III built.

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