Jaguar XK8 and XKR buyer's guide

Every early XK8 has a ticking time bomb of a Nikasil engine.

Many early cars received replacement steel-lined engines under warranty, and the problem was linked to high-sulphur fuel. A car with documented history and a good compression test is a different proposition from one with no records.

The gearbox is sealed for life, so it never needs attention.

The factory called the fluid lifetime fill, but specialists recommend changing the fluid and filter at around 50,000 to 60,000 miles. Records of this work are a good sign.

A low mileage car is always the best buy.

Cars that have stood for long periods can suffer from thickened hood fluid, tired tyres, perished seals and corrosion. Regular use with full servicing is usually better.

An XKR is just an XK8 with a supercharger.

The 4.0 XKR has a different gearbox, CATS adaptive suspension as standard, larger wheels and its own styling details. It has its own checks, such as the supercharger drive belt and CATS dampers.

Bodywork and structure

Ford-era build quality is generally good, but neglected cars do rust in expensive places. Take a torch, a magnet and a mat, and look underneath as well as along the panels.

• Front footwells: steel plates in the floor can trap water and rot from within. Lift the carpets if the seller allows and feel for damp.
• Sills along their length and at both ends; the front end hides behind a cover and mudflap. The sill joint below the door handle can crack, more so on convertibles.
• Jacking points and the sill areas around them, looking for crushing, fresh underseal or filler.
• Rear wheel arch lips and the rear quarter panel behind the wheel. Rot hides behind the plastic splash guards.
• Chassis legs where they rise in front of the rear axle, and the rear suspension mounting points.
• Front chassis legs behind the subframe turrets, viewed from inside the front wheel arches. Serious rust here is a major job.
• Rear bumper mountings: the brackets and fixings can corrode, letting the bumper sag. Check it is firm and the gaps are even.
• Paint: bumpers in a slightly different shade, peeling lacquer (more common on metallic colours) and overspray all suggest past repairs or resprays.

Engine

The AJ-V8 is smooth and strong when maintained. The key questions are which engine is fitted, what has been done to the timing gear and water pump, and whether the cooling system is healthy.

• Nikasil (early 4.0 litre cars): ask for invoices showing a replacement engine and have the engine number checked by a specialist or club. Without proof, a compression test is worthwhile.
• Nikasil wear shows as poor starting, uneven running, lack of power and high oil use.
• Timing chain tensioners and guides: listen at a cold start for a rattle from the front of the engine. Ask for proof that upgraded tensioners have been fitted on 4.0 litre cars. A failed tensioner can wreck the engine.
• Water pump: look for coolant stains, crusty deposits or a sweet smell around the pump at the front of the engine. Early pumps had an impeller prone to failure, so ask whether it has been replaced.
• Cooling system: it holds a small volume and does not tolerate leaks. Check hoses, the expansion tank and coolant colour, and watch the temperature gauge.
• Head gasket: a mayonnaise-like emulsion under the oil filler cap, oil in the coolant or white exhaust smoke are reasons to walk away.
• Auxiliary drive belt: cracks or splits mean it is due. A failed belt stops the water pump and power steering. On the XKR, check the separate supercharger belt as well.
• Oil cooler hoses on 4.2 litre cars, at the front near the radiator, for wear and seepage.
• Warning lights: ask for a code read. Lambda and knock sensors are common culprits.

Gearbox and drivetrain

Every X100 is automatic. Identify which gearbox the car has before the test drive, and check whether the fluid has ever been changed.

• XK8 4.0 litre cars use a ZF five-speed automatic; 4.0 XKRs use a Mercedes-Benz five-speed; all 4.2 litre cars use a ZF six-speed.
• Look for invoices showing a fluid and filter change at around 50,000 to 60,000 miles, despite the original lifetime fill claim.
• Shifts should be smooth up and down. Slipping, flaring revs or harsh, jerky changes can mean wear or a blocked filter.
• On six-speed cars, a gear ratio warning or limp-home mode on a high mileage car points to a tired gearbox.
• Look underneath for fluid leaks from the gearbox and around the rear axle, and ask whether the gearbox has ever been replaced.
• Worn engine mountings show as excessive engine movement or a clunk when pulling away hard or braking.

Suspension, steering and brakes

The car should feel tight and composed. Knocks, wandering or uneven tyre wear mean worn parts somewhere.

• Uneven tyre wear across the tread suggests worn ball joints, bushes or poor alignment.
• Knocks and rattles over bumps usually mean worn bushes; front wishbone bushes and the rear subframe and damper mountings are worth checking on a lift.
• Front wheel bearings wear; listen for a hum or roar that changes with speed.
• CATS adaptive dampers, standard on the XKR and optional on the XK8: confirm there are no warning messages and no leaks, as replacements are costly.
• Brakes: feel for judder from warped discs and ask when discs and pads were last replaced, as larger Brembo systems are expensive to renew.
• Wheels: check for kerb damage on 18, 19 and 20 inch wheels with low-profile tyres, and that they are genuine Jaguar wheels in a matching set.

Electrics and instruments

Electrical faults rarely stop the car but can be slow and costly to diagnose. Test every switch and feature.

• Remote central locking: if a fob stops working the problem may lie with the controlling module, which is no longer made. Two working keys and fobs are an asset.
• Electric seats: wiring under the front seats can be pinched and blow a fuse. Run each seat through its full range.
• Electric steering column adjustment: check it moves fully; the cable is the usual weak point.
• Windows, mirrors, heated seats, cruise control and the column stalks, including the trip computer.
• Instrument panel and displays for missing segments or warning lights that stay on.
• Headlamps for cracks or misting, as replacement units are expensive.

Convertible hood

The power hood is a highlight when it works. Operate it several times during the viewing.

• It should open and close smoothly and fairly quickly without hesitation, stopping or unusual noise.
• A slow or sticking hood, often worse in cold weather, usually means thickened hydraulic fluid, which should be renewed every five to six years.
• Look for hydraulic fluid leaks or staining around the rams and in the hood well and boot.
• When closed, the hood should latch securely to the screen frame and seal properly against the windows.
• Check the fabric for rips, worn creases and shrinkage, and look for water stains inside, as a new hood is expensive.
• Test the heated glass rear window element.

Interior and trim

Cabins wear well when cared for, but leather, wood and headlining all cost money to put right.

• Front seat side bolsters for wear, cracking and splits, especially on the driver's side.
• Wood veneers for lifting or cracked lacquer. Classic trim has walnut and full leather; Sport trim has maple veneer and cloth seat inserts.
• Coupe headlinings for sagging.
• Carpets and footwells for damp, which may point to hood, seal or screen leaks and to floor rust.
• Trim colour and veneer matching the original specification, as later replacements can look out of place.

Paperwork and originality

On an X100 the history file is the car's best defence. Invoices matter more than stamps.

• A full service history with invoices, not just stamps, and explanations for any gaps.
• Proof of engine replacement on early 4.0 litre cars, or of upgraded timing chain tensioners and a replacement water pump.
• Gearbox fluid and hood fluid changes recorded.
• VIN and engine number checked against the V5C, and the number of former keepers.
• Online MOT history for recurring advisories, mileage consistency and corrosion notes.
• Evidence for any claimed special edition, such as the Silverstone, XKR 100 or Carbon Fibre.

Which Jaguar XK8 engines have Nikasil bores?

Early 4.0 litre engines, built until the switch to steel liners around late 1999 into 2000. Many were replaced under warranty, so check the history file, any engine bay plate and the engine number with a specialist or club. All 4.2 litre engines have steel bores.

What are the main problems with the Jaguar XK8?

Nikasil bore wear on early 4.0 engines, plastic timing chain tensioners, water pump failure, gearbox wear without fluid changes, rust in floors, sills, arches and chassis legs, thickened hood fluid and electrical faults.

How do I know if the timing chain tensioners have been replaced?

Look for an invoice that specifically mentions upgraded tensioners and guides. Listen for a rattle from the front of the engine in the first few seconds after a cold start. If there is no evidence on a 4.0 litre car, assume the work needs doing.

Is the XK8 gearbox really sealed for life?

The factory described the fluid as lifetime fill, but specialists recommend changing the fluid and filter at around 50,000 to 60,000 miles. Smooth shifts and records of a fluid change are good signs.

Should I buy an XK8 or an XKR?

The XK8 is smoother, quieter and cheaper to run. The XKR is much quicker with adaptive suspension as standard, but adds the supercharger belt, costlier dampers and higher fuel use. Condition and history matter more than the badge.

Is a 4.2 litre car better than a 4.0?

The 4.2 has steel bores from the outset, more power and a six-speed gearbox, which suits buyers who want to use the car regularly. A well documented 4.0 with a replacement engine or proven history can be just as sound.

Why is my XK8 convertible hood slow?

The most common cause is old hydraulic fluid that has thickened, which is often worse in cold weather. The fluid should be renewed every five to six years. Also check for leaks and electrical faults.

Is a Jaguar XK8 a good first classic?

It can be, if you buy a well documented car and budget for specialist servicing. It is easy to drive, but complex, and neglected examples are expensive to put right.