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Jaguar XJ40

Published: 26th Apr 2011 - 0 Comments - Be the first, contribute now!

AJ6 engine is quite sturdy although piston and head gasket failures are common AJ6 engine is quite sturdy although piston and head gasket failures are common
Typical Jag luxury; Daimler versions are really plush and all are comfy and refined Typical Jag luxury; Daimler versions are really plush and all are comfy and refined
Metric-sized rims can be a pain when it comes to tyre replacements as they are dearer. Metric-sized rims can be a pain when it comes to tyre replacements as they are dearer.
XJs can rot badly in all the usual and the not so usual areas! Boot areas can rot completely out. XJs can rot badly in all the usual and the not so usual areas! Boot areas can rot completely out.
Trim stamina can be suspect; cracking armrests very common and veneer age prematurely. Trim stamina can be suspect; cracking armrests very common and veneer age prematurely.
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What is a Jaguar XJ40?

Incredible as it may seem, the XJ40 is 20 years old next year, although strictly speaking, it’s an XJ6 as XJ40 was only Jaguar’s code name. But it bore little resemblance to the outstanding Series 1, 2 & 3 that preceded it. It was Jaguar’s first tentative step into a new world - a world of modernity and electronics. The result is a truly efficient car, every bit a match for the contemporary BMW or Mercedes. Little was carried over from the outgoing cars and so the XJ40 was almost a clean sheet design. Unfortunately, it also meant that the car was introduced before the development programme had finished and those early cars were plagued with faults. As it aged, Jaguar got on top of the problems and in the later years produced a very fine car indeed. But mud sticks and although most difficulties have been retrospectively sorted, values are seriously affected.


Jaguar’s mighty XK engine, always destined for the MkVII, had its public unveiling in the XK120. Later, the silky smooth V12 burst onto the scene in an E-Type, when its actual development was directed to the XJ saloon. So when Jaguar produced an all-new fuel injected, twin-cam, multi valve, sixcylinder engine in 1983, coded AJ6, it was only natural that the XJ-S should be its platform. By the time the XJ40 was unveiled in 1986 (after a reputed 14 year development run!), the 3.6-litre was a well proven unit. Looking at the valuable sub- 3.0-litre European tax bracket, a single cam 2.9 litre unit was also listed. Interestingly, it was a conscious decision by the designers to make very sure that a vee-engine would not fit in the bay.

In those pre-independent days, the fear was that the Rover-based V8 would be forced on the company. It then took a considerable amount of re engineering to accept the superb V12 engine, so much so that it would not be until 1993 that the job was finally done. In the meantime, the Series 3 soldiered on as XJ12, with solid sales despite the older shape. Technologically, the XJ40 was far superior superior car to the ageing XK-engined series. Both 3.6 and 2.9-litre engines were smooth and oil tight (a plus for Jaguar) and were coupled to equally efficient four-speed automatic or five-speed manual gearboxes. Even the final drive was new, and although Browns Lane’s incredibly competent IRS (independent rear suspension) carried on in the XJ-S and even the Aston Martin DB7, a simplified and more efficient system was used.There was nothing exceptional about the styling; in fact it is about as neutral as can be. But in the right colour, it is a very handsome car.

The package proved to be quite something, making an XJ40 one of the best handling (if not THE best) car in its class. The author (Jag expert Jim Patten remembers driving one on announcement in company with the Series 3 and frankly, it was in a different league. As a nod to Jaguar’s phenomenal success on the racetrack in the eighties, the XJR, with its handling package and body kit, was developed in conjunction with Tom Walkinshaw, who had masterminded Jaguar’s competition assault. Available from 1988 to 1989, there was a hefty price to pay - some £8000 on top of the bog standard model. The model itself though, never raced.

In 1989, the 3.6 engine was enlarged to 4.0-litre, while the 2.9 was abandoned in favour of 3.2, now topped by twin cams. There was even a Majestic long wheel base model for 1992. Various specifications were offered, and being Jaguar, even the basic level was good. At the bottom of the ladder was a 2.9 with cloth trim, no air- conditioning and probably manual transmission. Power steering, electric windows and a decent sound system all came as standard, but leather and air were options. These and more beside were loaded into the Sovereign spec cars which, of course, become more desirable on the used market. By 1994, it was all over for the XJ40 and the more curvaceous X300 took over the reins. So similar was this car that specialists were simply buying X300 front wings and boot-lid and converting XJ40s to make it look like the later model. It’s a funny old world.


To drive a well-sorted XJ40 today is still an experience. They are absolutely planted on the road. Drive a bad example and, well – it’s still pretty good. And that is a problem when looking at one used, especially if you’re coming from a more mundane sector of the market. Just how can the inexperienced judge between good and bad? Hopefully, our listings will help.

All engines are smooth and, with the exception of the 2.9, offer a level of performance way above most cars with sporting pretensions. Opt for a manual car and the enthusiast in you can be let loose as it is truly rewarding. It is a big car and those not used to this kind of bulk may find it intimidating at first, but be patient, the car almost shrinks around you. The realisation soon dawns that this Jaguar can be hurled around like a GTi. The brakes are well up to hauling the weight down in a very short distance and with bucket loads of torque, the bigger engines can catapult the cars out of bends. In top 4.0-litre and XJR guises, the Jag is a seriously quick car on country roads or the motorways and yet, when the mood strikes, is like a pussy cat trickling along at more sedate speeds. Despite this performance, the XJ40 can be quite economical.

Many a driver has seen 30mpg on a gentle tour. Even driven hard, the figures rarely drop below 20 mpg unless the driver is a real road hooligan. These are figures that any MGB owner would be glad of, as they would a near 140mph maximum speed and a zero to sixty dash in seven seconds.


Rock bottom. In fact we’ve heard of cases where cars have actually been given away! It is unlikely that any in the range will fetch more than £3000 - and that would be the ultrarare XJR 3.6 (or top V12 models). Realistically though, it is quite feasible to buy a perfectly good, low spec car below a grand. For this amount, expect to get a very decent 2.9 – if performance is not your thing, then why spend more to achieve the same level of trim? Spend another £500 and you’re into decent 3.6 territory. A little more gets the glorious four litre. Interestingly, manual transmission (one of Jag’s best efforts incidentally) holds no premium. In fact, in certain circles they are considered less desirable.

This is one car that is specification sensitive. Air conditioning and leather trim are all important, while the Sovereign badge is valuable currency. In many ways though, the purchase price is almost irrelevant. At the end of production, the top range models were leaving the showroom with price tags in excess of £40,000. The fact that you can now buy this car at ten per cent of that figure is impressive indeed. But remember that it is still a £40K car, requiring £40k car maintenance. Once you’ve got over that shock, it’s not as bad as it seems as the after market specialists ease the situation considerably.

Pick up a bargain

Saving the coffers With top spec cars in demand, there will always be that low mileage 2.9 manual with cloth trim as the unloved. It will still be a refined car and if everybody was honest about it, cloth is actually more comfortable and not so sensitive to temperature changes as leather anyway.

To restore or not to restore? Definitely not! The costs would be astronomic. Better to look at upgrading. If you must have leather trim, it can be sourced pretty cheaply enough.

Shifting around Where in the past many with a sporting side preferred a manual gearbox, the jury is still out on XJ40. Many like their big Jaguars to be automatic, shunning the clutch pedal. But a new breed of press-on drivers is making an impact so if a manual shifter is offered, snap it up.

What To Look For

  • Rotten rust. It was hoped that the XJ40 would escape the bugbear of corrosion but as time has progressed, it is popping up all over the place, especially on early cars. Find a good one and have it rust treated immediately…avoid remotely dodgy cars.
  • First glance. Go straight to the bootlid and look at the lower edge by the slam panel – it is most likely bubbling, as will the front of the bonnet. Parts are available, expensive at the factory but relatively cheap second-hand. Source from late models if possible. Corrosion attacks everywhere but at least externally it will be self-evident (unless bodged). Take a magnet and check the bottom of the doors and wings. Look out for the ‘A’ posts as these can corrode and are difficult to repair correctly.
  • Water in the boot is a real problem and easily fixed. Water gets past the cover plate on the slam panel. Just drill out the rivets, apply sealer and rivet back. Complete boots have corroded out due to this.
  • How about underneath? Pop the bonnet and check the inner wings, they can corrode with vigour. Difficult to bodge, it is hard to disguise- thankfully! Look around the brake master cylinder too; fluid leaks will lift the paint allowing rust to take hold.
  • With so many cars around and an overlap with the X300, parts supply is in abundance. Breakers also hold a large number of parts as repair can be expensive and good cars are consigned to the scrapheap ahead of time. Capitalise on their owners’ lethargy!
  • Engines are pretty well bomb proof. Obviously there are exceptions but in the main, this is one unit where 200,000 miles is not uncommon. In fact many breakers end up selling their units as scrap due to limited demand. But the clock ticks by so do not take this for granted. Problems so far encountered are head gasket failure and some piston breakage. Most of this can be put down to poor servicing and low-grade fuel. Given that it has been looked after, the V12 is long lived. Any sign of overheating or noises, walk away.
  • Will this Jaguar overheat like the older cats? So far, overheating has not been an issue on six cylinder cars. Should the engine run hot then it is most likely to be a blocked radiator or even debris between the radiator and air-conditioning condenser.
  • Jaguar filled the XJ40 with electronic devices, how reliable are they? Ultimately most devices work well but many faults were showing up on early models. Replacement modules are frighteningly expensive. The bulb fail modules for example, are around £140. However, as most problems are usually no more than a dry soldered joint, any competent electrician could put it right. A cottage industry has sprung up offering exchange units.
  • Is the gearbox as tough as the engine? Astonishingly it is, both in automatic and manual form. In fact another thriving industry has sprung up retrofitting both automatic and manual gearboxes to Mk2s and E-types. Clutches too are long lived and if a change is needed, it can be done with the engine in situ. A decent workshop can do the job in half a day. Check automatic gearbox oil for colour it should have a red hue. Dark brown with a smell of burning spells trouble, although this J-gated auto box is a pretty robust affair.
  • Pulling to one side is almost directly attributed to worn wishbone bushes or ball-joints. Replacement is routine although a special coil spring compressor is needed to attack the inner bushes. The Jaguar Enthusiast Club offers a hire service. At the rear, the final drive frame is mounted on bushes in an ‘A’ frame. Relatively easy to fix, but a professional press is needed to push the new bushes in.
  • Rear axles can be troublesome. Two types of differential were fitted, Dana and Salisbury. Salisbury is more reliable and often given by Jaguar on exchange, regardless of what is requested. Output shaft bearings wear and, if caught early enough, can be cured by a localised repair. Second-hand units from a known good car is a decent option to consider.
  • When a car sits low at the rear without a load on board, then suspect the self-levelling dampers. Linked to the braking system, green fluid (Citroen style) is pumped to adjust ride height. It will fail. Later models reverted to conventional dampers and a conversion is available from both Jaguar and the specialists. Rear suspension geometry was never good when new and may be ‘out’. Have the car checked on a modern four-wheel laser alignment system.
  • Good car, scruffy interior – what can be done? With so many cars broken for spares, the sky is the limit. Daimler leather, electrically adjustable seating, it is all available – and cheap too. Bleached wood and lifting veneer can really spoil the effect. Jaguar still keep some in stock but again, specialists offer an economic alternative. Oh by the way, broken door locks are very common on this car and it’s an MOT fail point.
  • Early models were fitted with metric wheels and tyres, is this likely to be a problem? There is no doubt that metric rubber is expensive. But companies like Colway offer speed rated remould tyres. Don’t doubt their efficiency, many rally drivers use their products. Another option is to convert to imperial size by sourcing from later cars or certain XJ-S.
  • Find a car with a full service history and be delighted. These cars will deteriorate if neglected. Better 100,000 cared for miles than 50,000 neglected ones. A fully stamped (and verified) service book is worth its weight in gold.



If ever there was a future classic in the making, the XJ40 is it.We reckon that buying the best possible example today will pay dividends tomorrow. So many are being broken for spares through even the tiniest of faults that the numbers of remaining cars will eventually be quite low. The great thing is that if it doesn’t work out, there isn’t too much to lose. In fact, even with the running costs of fuel and servicing, it is still probably cheaper to run an XJ40 for a year and throw it away at the end than it would be to suffer the depreciation of a brand new car. Especially if you happened to have bought a Rover…

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