Jaguar XJ6, XJ12 & XJC Buying Guide

No car has ever matched the combination of grace, space, pace, luxury and affordability of the Jaguar XJ

• Project £1000-3000 • Good £4000-8000 • Concours £9000-20,000 •

Practicality ★★★★
Running costs ★★★
Spares ★★★★
DIY Friendly ★★★
Investment ★★★
Desirability ★★★★

Jaguar has had a habit of moving the goalposts with its most significant models. That’s certainly the case where the XJ is concerned, which was good enough to scoop the Car of the Year award in 1969. When it arrived in 1968 it replaced the 240/340, S-Type, 420 and 420G, and while it initially came in six-cylinder form only, before long it would also be available with V12 power – the only car in its class.

While no XJ is frugal and the V12 can be downright crippling, a good six-cylinder XJ represents excellent value and offers a sublime ride and relaxing drive.

Low values for decades means many XJs have been run on a shoestring, so poorly maintained and bodged cars aren’t rare, but there are also some very good examples out there which are now starting to be worth significant money – especially in two-door coupé form.

Your AutoClassics Jaguar XJ inspection checklist


Around two-thirds of the XJs built were fitted with a six-cylinder engine; the rest got a V12. The XK straight-six must be looked after if it’s not to wear prematurely, so start by checking the oil level, consistency and colour. If the oil is thick and black just walk away, or budget for an engine rebuild sooner rather than later.

The XK engine has an alloy cylinder head so the coolant’s anti-freeze concentration must be maintained, to stave off internal corrosion. If the coolant becomes too dilute the radiator will block up with debris.

A healthy XK engine will use some oil, but if the valve stem seals have hardened or the valve guides have worn there will be significant amounts of blue exhaust smoke. There should be 40psi of oil pressure when cruising; if it’s significantly less a rebuild is due. If the underside of the engine is coated in oil the rear crankshaft oil seal has probably failed. Putting this right is part of a full engine rebuild.

Uneven running is often down to problems with the fuelling. While some XJs are injected, others have SU carburettors. The latter have an automatic choke which fails, but it can be converted to a manual set-up – although this in turn can be unreliable.

The V12 engine is as unstressed as they come and will last indefinitely if looked after. What will wreck a V12 is overheating; again, anti-freeze levels much be maintained and the oil changed regularly. If a rebuild is needed, get saving because the V12 features a lot of components...


Most of these cars have an automatic gearbox, but some six-cylinder examples got a manual transmission. Until 1977 a Borg Warner auto was fitted; later V12 editions got a GM400 gearbox.

Series I autos aren’t very smooth but later cars are better. If maintained these automatic transmissions last well, but rebuilt units are easy to find and they’re not especially costly. The manual gearbox is similarly strong and most came with overdrive. If this is slow to engage the oil is probably low or it may be that an oil change is needed.

Rear axles last forever but they can leak, which leads to oil getting onto the inboard rear brakes. Fixing this is costly, not least of all because the diff and rear brakes need to be completely overhauled. Any clonks will be from worn universal joints, but these are cheap to fix.

Suspension and brakes

Power steering was standard from the outset, and although the system is normally very reliable you still need to check for leaks. Look for these underneath the car and also check the fluid level from the engine bay.

If the tyres have worn unevenly it’s probably because of tired suspension and rear subframe bushes. Because there are so many suspension bushes throughout the car, replacing everything is very costly, but normally not all of them need to be renewed.

The in-board rear brakes are often neglected and on cars used only occasionally they can rust, so do your best to check their condition. The handbrake has its own calipers and pads, which can seize up, and fixing this is awkward so check that it works.

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Rusty and bodged XJs abound thanks to poor rustproofing, low values and often a low standard of production on the assembly line. Rusty and poorly restored cars are rife, so home in on the sills, A, B and C-posts, valances and rear wheel arches along with the door bottoms and the spare wheel well.

The rear radius arms and their mounts rot, as do the front and rear screen surrounds (particularly on the Series III) and the bonnet hinge mounting points. You can also expect corrosion in the bonnet, boot lid and front wings (particularly around the headlights) along with the jacking points.

Finish off by looking at the radiator support frame, which is a big job to fix on an XJ6 and it’s even bigger on an XJ12. A rotten front subframe is also likely, particularly on the Series 2 and Series 3.


The XJ’s interior should be sumptuous; a few were trimmed in cloth but the great majority are swathed in leather. This can crack and split while the carpets wear and wood can delaminate. Fixing everything will be expensive, so check everything closely.

The electrical system of the Series 1 and Series 3 tends to be fairly reliable but the Series II is usually more problematic. It’s the switchgear that gives the most trouble, especially the electric window controls. Everything is available but pinpointing what the problem is can take time.


*1968: The XJ6 replaces the S-Type, 240, 340, 420, 420G and Mk2.

  • 1969: The Daimler Sovereign goes on sale.
  • 1972: The XJ12 and Daimler Double Six join the range, along with the Vanden Plas Double Six.
  • 1973: Production of the short-wheelbase models ceases.
  • 1974: The Series 2 XJ arrives and the XJ Coupé reaches showrooms. The final 2.8-litre cars are built.
  • 1975: New arrivals include the XJ6 3.4 and Daimler Vanden Plas 4.2. All V12s now have fuel injection, while all XJ12 saloons get a vinyl roof.
  • 1977: XJ12s now have a GM400 automatic transmission and the final coupés are built.
  • 1978: Fuel injection is now fitted to 4.2-litre cars.
  • 1979: The Series 3 goes on sale and six-cylinder cars now have the option of a five-speed manual gearbox.
  • 1981: V12 engines are now to HE (High Efficiency) spec.
  • 1982: Six-cylinder cars get a Borg Warner Model 66 automatic transmission.
  • 1987: The final XJ6 is built.
  • 1989: V12s can now officially use unleaded.
  • 1990: Anti-lock brakes become standard.
  • 1991: The final XJ12 is built.
  • 1992: The last Daimler Double Six is produced.

AutoClassics says…

It’s obvious advice but it’s amazing how many people don’t heed it: be scrupulous with your checks and don’t buy a dog, because that’s exactly what many people do. Restoring a project could bankrupt you unless you have very deep pockets or you’re multi-talented in the workshop.

There were lots of different XJs available across the three series, including standard and long-wheelbase cars, saloons and coupés (the latter in Series 2 form only), six- and 12-cylinder engines and manual or automatic transmissions. Pinning down which suits you best can be difficult but don’t focus too much on spec; the condition matters more.

For most buyers the ideal car is a 4.2-litre Series 1 or Series 3; the Series 2 is generally sought after only in coupé guise as this was the generation built to the lowest standard. The 2.8-litre engine is unusual and underpowered which is why a 4.2 is more sought after, although a 3.4 is a good option too. Don’t be put off by the V12 if you do only a few miles each year; it will always cost more to run one of these than a straight-six, but buy well and the costs are surprisingly manageable.

There’s also the Daimler badge to throw into the equation; don’t forget to look for one of these more unusual editions because if you can’t find the Jaguar XJ of your dreams you might have a bit more luck tracking down the perfect Daimler.


XJ6 Series I 2.8
  Power 140bhp
  Top speed 117mph
  0-60mph 11.0sec
  Economy 19mpg

XJ6 Series I 4.2
  Power 173bhp
  Top speed 124mph
  0-60mph 8.8sec
  Economy 15mpg

XJ6 Series I 5.3
  Power 253bhp
  Top speed 147mph
  0-60mph 7.4sec
  Economy 12mpg

XJ6 Series II 3.4
  Power 161bhp
  Top speed 189mph
  0-60mph 11.7sec
  Economy 18mpg

XJ6 Series III 5.3
  Power 299bhp
  Top speed 142mph
  0-60mph 8.1sec
  Economy 16mpg

Jaguar XJ cars for sale here.

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