Free guide · 1998–2006 · AJ26 / AJ34 supercharged V8 · 370–400 PS
Jaguar XKR X100: what to check before you buy
What this car is, and the six questions that decide whether the one you are looking at is a good buy.
In this guide · 6 chapters
Who built it, and what they built
The XK8 replaced the XJS in 1996 and did something Jaguar had not managed in twenty years: it looked like the E-Type's descendant without looking like a tribute act. Then in 1998 they put an Eaton supercharger on it and called it the XKR.
What you get is an English grand tourer with a supercharged V8, a shape drawn from the most beautiful car anyone has ever built, and a price that has fallen to what a used family car costs. Nobody is going to make one of these again.
The engine, and there are two of them
The 4.0-litre AJ-V8, 3,996 cc, with an Eaton supercharger: 370 PS, from 1998 to 2002. Paired with a five-speed automatic of Mercedes origin.
The 4.2-litre AJ-V8 from the 2003 model year, 4,196 cc, 400 PS, with the ZF six-speed automatic.
Both are supercharged V8s, and the difference between them is not really the power. It is that the plastic timing chain tensioners are above all an early-car problem — but the sources do not agree on when they went away, so the year alone does not settle it. On any XKR the question is which tensioners are in it now, and that is the single most important question in this guide.
Why this car is unusually buyable
Because both of its famous faults are binary and cheap to establish.
The Nikasil question is answered by the engine number, and the VIN narrows it down before you travel. The chain tensioner question is answered by a cold start and the paperwork. Between them, a few minutes at the car tell you which of two very different cars you are looking at — and neither check costs anything.
Compare that with a rod-bearing interval you can only read from an invoice, or a clutch percentage that is accurate to within ten per cent. This is a car where the buyer can actually know.
How the figures in this guide work
No euro totals: a labour rate differs by country and by workshop. Each job carries a step on a scale of five — an hour or two, half a day, a day, two or three days, a week or more in the workshop — plus one line on where the work sits.
Where a source gives a price, it stays out of this guide: a quote from one country tells you little in another. What the sources do give on this car is the scope of the big job, and it is unusually precise. A known fault with a fix of known scope is rare, and it deserves to be stated plainly.
The six questions that decide whether this car is a good buy
1 · What does the engine number say about the bores?
The engine number carries the date the engine was built, and one specialist reads the bores straight from it. The VIN narrows it down before you travel, but on its own it does not settle it. The date that divides the two, and how to read both numbers, is in the buying guide.
2 · Does it rattle for a few seconds on a cold start?
An early car has a known reason to, unless the parts have been replaced, and a 4.2 is not automatically in the clear. What the rattle points to, and how to hear it properly, is in the buying guide.
3 · Has the chain job already been done — and to which specification?
There is a right specification and a like-for-like one, and only one of them closes the question.
4 · Is there a whine that rises and falls with the revs?
Every one of these whines; it is supercharged. Whether it is the right whine is the question.
5 · What do the sills, the rear wings and the floor under the battery look like?
This is a steel car, and the sources call corrosion a serious problem in several places. It is not an aluminium Aston.
6 · Any coolant loss — and on a 4.2, have the valley pipes been looked at?
They are not easy to reach, which is why the answer matters.
What the honest answer to all six looks like
A 4.2 — steel liners by definition — with an invoice for the right tensioners, a dry engine and solid sills is a car you can buy on the answers. An early 4.0 that rattles on start-up, with Nikasil bores and bubbling sills, is not necessarily a disaster — but you are looking at three separate jobs, and the price should say so.
Which years, which specification
1998 to 2002: the 4.0, 370 PS, five-speed automatic. Plastic timing chain tensioners, unless they have been replaced.
Late 2002 to 2005 (model years 2003 to 2006): the 4.2, 400 PS, ZF six-speed automatic. Improved tensioners — but the sources do not agree on when the durable type arrived, so ask here too.
The Nikasil date. What counts is the date the engine was built — not the car, and not a model year — and the engine number carries it. A buyer's guide dates the switch to steel liners to October 1999, and a specialist puts it later, so the sources do not agree on the date. What the VIN can and cannot tell you is in the buying guide; the engine number is what settles it.
What that means when you are shopping. The 4.2 is the easier car on the two big questions: it never had Nikasil, and its tensioners were improved. The 4.0 is cheaper to buy and can be exactly as good — but only if the chain assembly has been done properly and the bores are accounted for. Both routes are legitimate; what is not legitimate is buying an early car and hoping.
One more difference worth knowing. On the 4.2 the sources name the valley pipes under the supercharger as the usual source of coolant loss. The water pump and the thermostat housing are worth a look on both engines.
What it is worth
No price list — it moves by country and by month. But this car has a valuation quirk worth exploiting.
Both famous faults have known, bounded fixes — and the market prices them as though they were unknowns. A chain job has a defined scope. Which bores an engine has is a matter of which side of a date the engine was built on, and the engine number carries the date. Neither is an open-ended risk once you know.
So the arithmetic is unusually clean:
The done car. A 4.2 with an answer on its tensioners, or a 4.0 with the chain invoice and an engine number that says steel liners. Pay the premium; it is smaller than the job.
The honest project. An early 4.0 that rattles, priced accordingly. Add the chain job and you have the same car as above. This can be the best buy in the range if the bodywork is sound.
The one to avoid. Any XKR where the seller does not know which tensioners are in it and the sills are bubbling. Two open jobs, one of them bodywork, and bodywork is where the money disappears without anything to show for it.
Compare entry prices, not asking prices — and on this car you can actually calculate the entry price, which you cannot on most of the others in this series.
What it is actually like to own one
An English supercharged V8 in a body descended from the E-Type, for the money a used family car costs. That is the whole proposition and it is not overstated.
What it asks in return is that you take the two checks seriously up front and the bodywork seriously forever. This is a steel car from the late nineties; the mechanical side is more predictable than the metal.
The habits that cost almost nothing:
- listen to it start from cold, every time, for the first few seconds
- keep an eye on the coolant, and know where to look — pump and housing on either engine, and the valley pipes on a 4.2
- look under the battery once a year, because a wet floor there starts quietly
What surprises people is how usable it is. This is a grand tourer, not a sports car pretending to be one: an automatic gearbox, a supercharger that makes its power low down, and a shape that people still turn round for. It is also the only car in this series where the most beautiful thing about it is free.
The buying guide — €24
Everything above is what the car is. This is what you check.
Six faults that belong to this engine, taken apart one by one, with how much work each repair is and how to tell which of them you are looking at. Ten things that are simply twenty-five years old, every one with how much work it is, what tells you about it at a viewing, and whether it has to be done now, within a year or two, or not at all. The sills, the rear wings and the floor under the battery — this is a steel car. What a proper chain job includes, and which of the two specifications closes the question. The viewing in six steps, including the two moments that come only once. The sentences you say to the seller, and how to build an offer out of what you found.
And a card you print and take with you — twenty-seven lines, in the order you do them. That comes as a separate file, because nobody wants to print a whole guide to take a few pages to a car park.
This is what one of the ten looks like
6 · The supercharger belt
An hour or two · the part Cheap, visible, and its condition tells you about the last owner. Neglect here is expensive.
Now, if it is cracked or glazed.
And this is how the card reads
- 2 · The cold start · the moment that comes once
- 3 · The engine bay, engine off
- 4 · On the lift · this is where the money is
- 5 · Inside
- 6 · The test drive
- 7 · The paperwork
What €24 buys, put next to what it saves
A Nikasil engine that has gone is a week or more in the workshop and a replacement engine. The check that tells you which bores you are looking at costs nothing: the engine number, which carries the date the engine was built. The guide is €24. It will not stop any of that from being needed — but it does tell you which of them you are looking at before you agree a price, and that is the whole of the difference between paying for a car and paying for someone else's postponed maintenance.
Why there are no prices in it
Because a price we cannot verify is worse than no price, and because a price would be wrong for most of the people reading this anyway. Workshop rates across Europe differ widely, and so do parts prices. A quote from a specialist in one country tells you nothing in another.
What does not change is how much work a job is — that follows from what has to come off the car. So every point in the guide says whether it is an hour or two, half a day, a day, two or three days, or a week or more in the workshop, with a labour figure where a source gives one. And it says whether the money sits in the part or in getting to it, which is what lets you tell a fair quote from a bad one.
If you want a figure, ask any workshop one question — what is your hourly rate? — and every effort level in the guide becomes your own number, in your own currency. One question, and the answer is actually true for you.
How this guide was put together
Because you should know before you pay for it.
- Every fault and symptom comes from a source the guide names, the manufacturer's own documents first. The effort levels are our assessment, unless a source gives the hours.
- On Nikasil the guide gives you both the cut-off date, read from the engine number, and the test after which, in one buyer's guide's words, a surviving engine should be a good buy.
- The effort of every job is counted item by item and checked against the list before every edition.
- It says as plainly what you can leave alone as what you have to do. Three of the ten age points start from leave it.
Leave your email address at the checkout and both files arrive straight away: one guide and one card, as two pdfs. No subscription, no account.
The full guide · €24
17-page guide, A4 and phone · 3-page inspection card · instant PDF · VAT included
Have every car inspected before you buy by someone who knows this engine. This is general information about the model and not advice about a specific car.