Jaguar XJ-SC Cabriolet V12 (1985 to 1988)

The XJ-SC was Jaguar's first open version of the XJ-S grand tourer, and a stopgap until a full convertible was ready. It arrived in 1983 with the new 3.6-litre AJ6 six-cylinder engine only, and the 5.3-litre V12 version followed in July 1985. Rather than a folding roof, it had two interlocking targa-style panels over the front seats, which lift out and stow in an envelope in the boot, plus a fabric hood over the rear section that folds down. A removable rear hardtop was also offered. The rear seats were removed, making it a strict two-seater with lockable storage boxes behind the front seats.

Converting a closed body was a complex process. Early cars were built at Castle Bromwich, sent to outside specialists in Coventry and Bedworth for the roof to be cut away, the structure reinforced and the hood fitted, then returned to Jaguar for painting and assembly. Contemporary testers found the result impressively free of rattles, helped by a stiffened transmission tunnel and extra bracing underneath.

With the V12 the XJ-SC is a quiet, fast and very refined touring car, paired with a three-speed automatic. It was overshadowed by the full Convertible of 1988, and many people overlook it today, but its limited numbers and unusual roof give it distinct appeal. Like any V12 Jaguar of the period, it rewards a well-documented car and punishes a neglected one.

• Built: XJ-SC 1983 to 1988; V12 version announced July 1985
• Body: two-seat cabriolet with twin removable roof panels, fixed cant rails and centre bar, folding rear hood; optional removable rear hardtop
• Engine (V12): 5.3-litre V12 in HE (high efficiency) form, quoted at 291bhp or 295bhp depending on source
• Engine (six): 3.6-litre 24-valve AJ6 straight-six, about 221bhp at launch
• Gearbox (V12): GM400 three-speed automatic
• Gearbox (3.6): Getrag five-speed manual, with a ZF four-speed automatic optional from 1987
• Brakes: discs all round, the rears mounted inboard beside the differential on pre-1991 cars
• Production: about 5,000 XJ-SCs of both engine types are generally quoted (one source gives 5,013), most of them left-hand drive. I could not verify a reliable split between six-cylinder and V12 cars

• 1983: XJ-SC 3.6 launched with the AJ6 engine. Built in small numbers to order, with outside firms handling the conversion and roof work.
• July 1985: XJ-S HE V12 Cabriolet announced, badged XJ-SC HE. Jaguar brought more of the roof fitting in-house, allowing larger volumes. Mechanically it matched the HE coupé, with air conditioning, an automatic aerial and burr elm veneers as standard.
• 1986: The HE boot badge was replaced by a plain V12 badge, and the veneer changed to burr walnut with inlays. A 1986 car should show these details.
• 1987: Sports suspension package offered as an option across the XJ-S range.
• 1988: XJ-SC replaced by the full XJ-S Convertible, which had a powered fabric roof and a further strengthened shell.

Bodywork and structure

Pre-1991 XJ-S bodies were not galvanised, and rust is the biggest threat. Start with the jacking points, which can hide serious corrosion, then the sills and closing plates, floorpans, the bottoms of the front wings where they meet the sills (the wings should sit flush), wing edges around the headlamps, doors, rear wheelarches, the lower front edge of the rear wings, the boot lid edge and the windscreen scuttle. Check the subframes and crossmembers too. Water that gets past the roof seals collects in the floor, so lift the carpets if you can and look for damp, rust at the seatbelt mountings and corroded wiring. Do not let anyone jack the car on the floorpans.

On the XJ-SC specifically, examine the seals around both roof panels and the folding rear section, look for water staining on the headlining and trim, and check that the panels and their locking levers fit snugly. Make sure both roof panels and the storage envelope are present. Inspect the rear hood fabric for splits and shrinkage, and check the rear window section.

Engine

The V12 needs its coolant changing every two years, as radiators silt up and the engine runs hot. Brown or rusty coolant, a temperature gauge that climbs past the midpoint or a clattering engine are reasons to walk away. Listen at start-up for timing chain rattle, which is common on high mileage engines. Look for oil leaks from the cam cover gaskets and oil pressure sender, and ask about exhaust manifold gaskets. Hunting at idle shortly after a cold start can point to the auxiliary air valve, while misfires may be ignition faults or tired plugs, which are awkward to reach. Check the cooling fans, hoses and air conditioning condenser.

Gearbox and drivetrain

The GM400 automatic is a tough unit. If the engine can be run, select drive and reverse and feel for prompt engagement. On the move, changes should be smooth and kickdown immediate. A knock from underneath often points to a broken or worn gearbox mount. Listen for differential whine, and look for oil leaks from the differential, because fluid can contaminate the inboard rear brakes.

Suspension, steering and brakes

The front upper wishbone bushes wear from around 50,000 miles, upsetting tracking and wearing tyres, so look for uneven tyre wear. The rear subframe carries the suspension and differential and has rubber mounts that perish. Check the rear hubs for play. Power steering racks leak, so look for fluid around the rack and listen for noise turning from lock to lock. The inboard rear brakes are harder to work on than outboard ones, and calipers and the handbrake can seize on cars that are used little.

Electrics and interior

Check every switch, gauge and warning light, plus the electric windows, mirrors, aerial and air conditioning, including its flap motors. The battery lives in the boot and a leaking one can rot the boot floor. Water in the cabin can damage control units. Inside, look for wear on the front seat bolsters, sagging headlining, and cracked or lifting veneer on the dash and door cappings, which is costly to restore properly.

Identity and paperwork

Check that the badging and veneer match the build year, and that the car is a genuine factory XJ-SC rather than a later conversion. A thick history file, especially records of coolant changes and cooling system work, is essential with any V12. Treat a missing service history as a serious warning.

Parts supply for the XJ-S is generally good, with new wings and repair panels, hoods and mechanical parts available from several well-known Jaguar parts suppliers. XJ-SC-specific items such as roof panel seals and trim are scarcer, so check what is present and its condition. Independent Jaguar specialists who know the V12 well are widespread in the UK. Clubs include the Jaguar Enthusiasts' Club (jec.org.uk (opens in a new tab)), which covers the XJ-S and offers inspection and technical help, and the Jaguar XJS Club (xjsclub.org (opens in a new tab)).

• When was the coolant last changed, and has the radiator been cleaned or replaced?
• Are both roof panels, the storage envelope and, if supplied, the rear hardtop with the car?
• Does the roof leak, and have the roof seals or rear hood been replaced?
• What rust repairs have been done, to which areas, and is there photographic evidence?
• What work has been done on the inboard rear brakes, rear subframe mounts and front suspension bushes?