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JAGUAR XK100/150 BUYER’S GUIDE

JAGUAR XK100/150 BUYER’S GUIDE

Posted by Matt Bell on 20th June 2019

The XK8 was smaller, lighter, and more affordable than the XJS that it sort-of-replaced, but does it represent an affordable slice of Jaguar glamour today? And what nightmares might await the unsuspecting?

The replacement for the venerable XJS was long overdue, and the XK8 that was unveiled at the 1996 Geneva motor show brought to the public a very new Jaguar. A car that would generate widespread appeal that the marque had been missing for too long. It almost seemed worth the wait that followed the deferred hopes that had been tied up in the XJ41 project, the infamous beginnings of the Aston Martin DB7. A new V8 engine, sleek styling, and a ride/handling balance worthy of Jaguar’s reputation made the new XK8, and the convertible and supercharged XKR that followed in the subsequent years, something for even the Germans to take notice of.

It may have shared some mechanical fundamentals with the XJS, but the XK8 featured an entirely new front suspension design – double wishbones on an aluminium subframe – and the Computer Active Technology Suspension optional across the range brought that same level of new-era polish to the dynamic package that had already done so for the Ferrari 355. The talents of the X100 XK8/R models kept it relevant through its decade-long life span, until its 2006 replacement the X150 XK series.

The new XK may have looked rather similar to the old one but featured an all-new aluminium body, unusual for a car of its class and twinned with class-leading structural rigidity. Big fundamental improvements over its predecessor and a more aggressive suspension setup provided it even more impressive sporting abilities for the keen driver, and certainly gave it a good chance against increasingly sharp competition. Still, it would prove to be less of a commercial success for Jaguar than the original X100 XK8/R, and even after a significant facelift in 2011 and a multitude of special edition models along with it, in 2014 it was phased out in preference to the smaller, more focused F-Type.

Today the X100 and X150 models can offer a great deal of what’s good about Jaguar for surprisingly little. But you just have to be careful.

Engine & gearbox

The XK8 was introduced with a 4-litre 32-valve V8 producing 290bhp, with the XKR using supercharged induction to hike that up to 370bhp along with a whopping 387lb.ft of torque. The later 4.2 litre models would arrive in 2003 with various revisions that have by now proven to make these engines the more desirable from a reliability and running point of view. Not to mention even more powerful.

The early 4.0 engines were fitted with the infamous Nikasil-coated cylinder walls that would react badly to the low sulphur fuels available at the time. At the turn of the millennium such fuels were phased out and so any cars with Nikasil liners (on cars built up to 18/08/00, with engine numbers up to 0008181043) that run smoothly today shouldn’t present any future problems. If you’re still concerned, the engine number is accessible underneath a black plastic cover on top of the block to the right-hand side of the front of the engine, and a test often referred to as the blow-by test can provide readings that will gauge the condition of any particular engine.

The next items to pay close attention to are the water pump and timing chains. Early water pumps are more fragile than later ones and are often upgraded – look for the two-piece metal-bodied parts – to avoid the consequences of breaking impeller blades. In any case, and even for the relatively more robust X150s, it’s worth looking through the history to ensure that money has been spent on the water pump and overall coolant system when necessary. Particularly for higher performance models, the cooling system is under more stress than most cars and so appropriately needs more attention.

This is also the case for chains and tensioners, which will ideally have been upgraded to the 4.2 specification of the all-metal cased type if not already. Otherwise the unpredictable failures of the upper chain tensioners of the 4.0 engines might keep you up at night. Less dramatic but still worth considering are the throttle body position sensors that can cost a few hundred pounds to replace and were revised on the post-2003 4.2 models.

This is not to say that the 4.0 isn’t capable of being reliable, when maintained and lightly modified where needed, and simply shares its later relatives’ need for regular servicing. Particularly on the more highly stressed supercharged units of the XKR, it’s worth listening carefully for rattling or rough running that might point to neglect or abuse in the past. Be sure to check the history, as rattling could also point to a failure in the hydraulic variable valve timing that is a known issue on X150s in particular and can be pricey to fix.

All gearboxes across the X100 and X150 range are ‘sealed for life’, but not many owners will accept this. ZF, supplier of XK8 five-speed and all X150 six-speed units now says that an oil change is advised at 60,000-mile intervals, the same as the Mercedes-Benz five-speed in the X100 XKR. Check that the filter has been changed too and even look out for replacement of the electrical connector sleeve – a common fluid leak point. Don’t fret if official Jaguar fluid hasn’t been used, as other fluid – specifically Mobil – has been verified as compatible by the trade and club members alike. If you plan to have the job done by a garage, it’s worth noting that the Mercedes-Benz gearbox of the XKR is actually the cheaper to do, as its dipstick makes refilling far easier.

Suspension & brakes

A car that so carefully balances excellent ride quality and incisive handling, while suspending over 1600kg of mass above big wheels and brakes, will inevitably endure stress on its suspension – particularly the bushes that support all of the moving components against the structure. The general rule is that these tend to wear out after 60,000 miles of use. Those on the front wishbones are particularly prone to wear, as well as the lower damper bushes. Subframe mounts can go sooner, at 40,000 miles or five years and can set you back over £500 to have replaced.

If you’re after a car with the optional CATS system, simply confirm its fitment by observing the wires connected to the top of the suspension struts seen under the bonnet. Perhaps unsurprisingly, a new damper as part of this system is expensive, so beware that the electronic components inside also tend to wear out at the 60,000-mile mark. A sign that these sophisticated units might be on their way out is a repetitive tapping on uneven surfaces taken at low speeds, so have an ear out.

Brembo brakes were an option, then standard on the XKR from 2003. These can cost double the already rather steep amounts required to replace the standard brakes, so approach the prospect carefully and ideally with a large bank balance or light foot. This premium can be even higher for the X150 XKR that has to reign in even greater performance.

Chassis & body

Thanks to a combination of complicated bodywork, underside fittings and our love of salting the roads, the plague of corrosion pays no sympathy to the beautiful bodywork of the Jaguar coupe and will tarnish its finish in a number of places. The usual rear subframe and wheelarches are affected and should be inspected carefully – ideally up on a ramp – as this can be seriously expensive to remedy. Towards the front, the outer corners of the floorpan are notoriously susceptible to rust and any owner in the know should have already taken proactive measures to protect this area.

Models after 2002 and the X150 are, fortunately, far less vulnerable in these areas, but good attention should still be paid underneath.

Despite having an aluminium body, corrosion isn’t a non-issue for the X150. Look at where steel rivets or bolts make contact with aluminium and have potential to effect galvanic corrosion. An obvious area to look is where the brake lines are clipped to the body, but a careful eye over all fixtures is also worth it.

The front undertray for example is held on by steel fixtures and can therefore be tricky to remove, so inspect the condition of these fixings too. It’s also been known for other bits of trim to wear against the aluminium and cause damage, so check the cabin openings where trim can scuff bodywork.

Any car that has done high miles, a natural thing for a V8-engined Jaguar coupe to have done, will likely have its share of cosmetic damage, particularly at the front. On X100 models check the leading edge of the bonnet for signs of corrosion where paint has been chipped away, as well as the condition of the lower bumper that could point to any weathering the underneath has endured.

The X150 models will be better protected against corrosion, but since aluminium is more fragile and difficult to repair, lighter impacts will have caused more significant damage. Bear any imperfections in mind and be prepared to spend a good deal of money rectifying or to simply tolerate them.

Pay the whole of the car’s body a more careful and patient look over to be certain of what you’re buying into. Most, understandably, will want a Jaguar XK that looks good.

Electrics & auxiliaries

The X150 offers a significantly more modern environment in which to travel, being one of the first Jaguars to push away from the traditional, even staid, image of the old Jaguar. For some, it will be far more desirable for this alone. But there’s more. Aside from the especially luxurious Portfolio model introduced in 2008, there was an extensive options list that would add to your now aluminium-trimmed cabin that from 2009 would also feature the dramatic rising gear selector.

But with fancy electronics come faulty electronics, and while the X150’s fittings are on the whole reliable, it’s worth going over all the buttons and checking everything works. If looking at a particularly highly specified car, check that potentially costly features such as the adaptive cruise control and active headlights work too.

In fact, check that all the headlights and indicators work on any X150, as the earth point by the offside wheelarch is unusually vulnerable to corrosion and damage which can cause such electrical issues.

Warning lights can come up from faulty sensors in the tyre pressure monitoring system as well as the three sensors placed in the front crash structure that are meant to identify pedestrians. You can find retrofit items that are thought to be more reliable, so evidence of this would be a nice sight in the car’s history.

X150s can also suffer from cabin ingress of moisture from clogged air conditioning drain tubes, ending up with water in the footwell. Be wary of what might hide under floor mats, and if there’s evidence of stained carpets but no moisture, check that a breather pipe has been replaced or modified and that the air conditioning still works – tracking down problems in a system that has been left unused for years can be surprisingly expensive not to mention tedious.

On all convertibles across the X100 and X150 ranges, the power hood system can benefit from occasional fluid changes, so any evidence of replacement will point to a thoughtful owner – or possibly a car plagued by problems.

Check that the roof goes up and down smoothly from beginning to end and doesn’t feel significantly strained at any stage. Early X100 models may still have their original fluid that has been known to coagulate and cause problems, so be particularly diligent on these cars.

Decisions and conclusions

Now that you’ve learned what you need to look for, you can better see what you want to look for. There is a wide choice of XK models. Early cars offer their own charm in their purity of design, but post-2002 X100 models with the 4.2 litre engines and six-speed gearboxes are arguably the better buy. From 2001 the XKR also received side airbags and a drive-by-wire throttle, and in 2003 it gained Xenon lights, Dynamic Stability Control, Electronic Brake Assist, and cruise control. Adaptive cruise control and a 320-watt Alpine sound system were options from this time.

The X150 was an inherently sportier car, not just for its gearshift paddles, and the performance is evident even outside the special editions. The XKR-S first appeared in 2008, then reappeared in 2011, then with the latest 5-litre V8 that was introduced in 2009. A healthy range of options and colours were available, even knocking out the X100’s sound system with a 525-watt Bowers and Wilkins one. But the fundamental choice between the two is a matter of old-fashioned style and comfort against more modern dynamism. Either will inevitably cost quite a bit to run, but so long as you’re careful the X100 and X150 can both be thoroughly rewarding cars to own.