Used XJ6, XJ8, XJR review and buying guide (2003 to present): which one to buy and what to check

Which used Jaguar XJ6, XJ8, XJR should you buy?

A petrol V8 is the safer buy, and the 3.5 already has plenty of pace, so there's no need to stretch for the 4.2. Every engine in this aluminium-bodied XJ comes with the same ZF six-speed automatic and its J-gate for changing gear yourself, so the choice comes down to which engine you're happy to live with.

The 2.7 V6 twin-turbo diesel is the one to approach with care. Its turbos get very hot and their oil seals are prone to failing, and a car used for short trips from cold clogs its particulate filter, which lets fuel run past the pistons into the sump. Only take one on if it's spent its life on long runs.

Which Jaguar XJ6, XJ8, XJR engines and gearboxes are the safe choices?

The petrol engines are the safer choice, because the turbo and filter trouble belongs to the 2.7 diesel. There's a 3.0 V6 in the XJ6, a 3.5 V8 and a 4.2 V8, and the XJR uses a supercharged 4.2. The 3.5 doesn't feel short of pace, and every engine uses the same ZF six-speed auto with a J-gate.

The 2.7 V6 diesel's turbos get very hot and their oil seals are prone to failing, so let the engine idle for a while before switching off after a hot-weather motorway run, a long climb or a spell of towing. Turbos fitted to some 2006 diesels were thought to come from a faulty batch, though switching off while they're still red hot is the other suspected cause of those failures.

Short trips from a cold start are the diesel's other enemy. They block the particulate filter, and the extra fuel used to burn it clean runs past the pistons into the sump, polluting the oil and pushing its level up until the engine can start running on it. A 2007 recall also covered the diesel's filter getting too hot, so ask for proof that work was done on any 2.7.

What should you check when viewing a used Jaguar XJ6, XJ8, XJR?

Corrosion around the bootlid, the door pillars, the bottoms of the doors and the wheelarches is the first thing to look for, because these aluminium cars corrode there more than you'd expect. The steel rivets holding the aluminium panels are to blame, since the two metals react where they touch, so look hard along every panel edge in those areas.

On the drive, take a tight corner briskly and listen for clonks from the suspension. Ask when the rear brake pads were last replaced and look at what's left on them, as they can wear out quickly. On a diesel, pull the dipstick: oil above the top mark means fuel has got into it, which points to a clogged particulate filter.

There are three recalls to ask about. In 2004 the six-speed auto was recalled over a software fault that could let it drop into reverse when travelling fast, and the same year a recall covered sharp dashboard edges that could puncture the airbags as they opened. The 2007 recall covers the 2.7 diesel's particulate filter overheating. Ask for paperwork showing each one that applies was done, and on a diesel ask how it's been used.

Paste the advert into the free check and it runs these against the listing, the MOT history and the DVLA record before you travel.

What do Jaguar XJ6, XJ8, XJR owners like about them?

It's good to drive, and even the mid-range 3.5 V8 has plenty of speed when you want it. The aluminium body makes it relatively light for such a big luxury saloon, and the J-gate on the automatic lets you hold a gear yourself rather than leaving everything to the gearbox.

The long wheelbase car's the one to have if you carry adults in the back, since it adds a useful amount of rear legroom and you could have it with any engine. The 2.7 diesel delivers its pulling power in a flat, even spread, so there's strong pull right across the rev range.

• The aluminium-bodied XJ6, with its 240bhp V6 engine, is relatively light at 1,630kg and accelerates to 60mph in 7.3 seconds.
• The XJR model offers 400bhp and 408 lb ft of torque, with all engines paired to a six-speed ZF automatic transmission.
• The car provides an enjoyable driving experience, delivering ample speed even from the mid-range 3.5 litre engine.
• A long wheelbase version, launched in April 2004, adds 125mm to the length, providing 999mm of rear legroom.
• The 2.7 V6 Twin Turbo diesel, introduced in summer 2005, achieves 35mpg combined and has low 214 g/km CO2 emissions.