The X350 chassis marked the first truly revolutionary change to Jaguar’s flagship sedan since the Series III chassis came into production in 1980. Remarkably the new platform’s interior and exterior styling conveyed so much of the prior car’s aura that many people failed to appreciate just how innovative it was.
Starting with a blank sheet Jaguar completely threw out the old architecture, focusing on creating a new all aluminium platform. The platform was anchored by bonded underbody components. These components were fused using aerospace-grade epoxy adhesives, providing incredible weight savings when compared to their traditional steel counterparts. To create the car’s unibody Jaguar employed nearly 3,200 self-piercing rivets to bring together the various stressed aluminium body panels. The end result was a larger, taller and wider sedan that weighed in at less than 3,500 lbs., or roughly the same as a lightweight sports coupe.
Coupled with the new models lighter weight and greater structural integrity were bored out versions of Jaguar’s prior V8’s. The prior naturally aspirated and supercharged 4.0 engines were increased to 4.2 liters. Bumping horsepower to 290 & 400 bhp respectively. Coupled with these power plants was a smooth shifting 6-speed transmission. Rounding out the car was an upgraded air suspension on all four corners, while the R series cars featured large Brembo brakes.
From 2007 through 2009 the car benefited from a mild face-lift, referred to as the X358. While the mechanicals and chassis remained the same, a number of changes were implemented to the exterior sheet metal to modernize and tighten the design. The interior also benefited from a few design tweaks resulting in increased legroom and a more ergonomic driving experience.
Advantages & Disadvantages:
The 2003-2009 XJ was a revolutionary vehicle for Jaguar. As such it benefited from numerous advantages:
• All Aluminum Construction
• Increased Structural Rigidity Offers a Superb Ride
• 4-Wheel Air Suspension
• Large Brembo Brakes with Equally Large Diameter Rims (XJR & R-1 Packages)
• Sport Mode Provides Crisp & Quick Shifts
• Classic Comfort & Elegance that only a Jaguar can Provide
• Robust Supercharged Power (400 bhp on XJR)
Jaguar’s though are historically finicky, so there are some disadvantages:
• “J-Gate” Auto/Manual Shifter is Almost Universally Despised
• Front Seats on Pre-2007 Models Take-up a lot of Space
• Cramped Interior Given the Sedan’s Size
• O.E. Brembo Brakes Wear Out Very Quickly
• Like Most Jaguar’s Repairs can be Expensive if you can’t do them Yourself
At the end of the day while this series of Jaguar “XJ” sedans do have a few quirks they are superbly engineered cars. Each section of this car was meticulously improved, thus bringing the gap that previously existed between Jaguar and its European competitors like Audi, BMW & Mercedes. The X350 model XJ sedan was the first modern Jaguar that could boast a design, build quality and performance on par with its sensual styling. .
Special or Desirable Options:
The X350 & X358 Jaguar XJ Sedans had a number of options, however, few of them can be considered rare. That being said opting for the “R” upgrade is definitely the way to go from a performance perspective. Notable options are as follows:
• 2003-2009 X350/X358 XJR – 7,316 Total Units
• Super V8/Daimler Super Eight – Long Wheelbase XJ
• Super V8 Portfolio – Long Wheelbase XJR (Only Available in Black Cherry & Winter Gold)
• R-1 Suspension Package – Includes Larger Rims, Upgraded Brakes and Tighter Suspension
• Two Tone Interiors – Cranberry is particularly rare
• Varying Wood Species – Species such as Elm, Boxwood, Walnut and even Aluminum was Available
What to look out for:
A Jaguar being a Jaguar will always be suspect to some peculiar issues. That being said, the X350 & X358 XJ’s were incredibly well built and showed excellent reliability ratings. The engines and drivetrains are pretty much bullet-proof, but certain suspension items can be tricky. With some of these cars being over 10-years old, there are certain areas that should be checked when purchasing a used model.
• Air Suspension: The XJ’s feature air shocks on all four corners. The shocks tend to leak which would cause the car to sag in one or more corners. The air compressors will also fail over time. If any of these issues exist there are repair and replacement services available, or the suspension can be changed to a coil-over system.
• Suspension Bushings: Many of the bushings in the suspension are prone to wear, especially in the rear. The items that are most prone to wear include the front & rear lower wishbone bushings, lower air spring bushings, rear sway bar & rear track rod bushings.
• Aluminum Corrosion: While the body won’t rust because it is aluminium, the subframes do have steel so they can rust. More important though is a degrading of the aluminium panels. This can happen in the inside of the front wheel arches, around the bottom rear window and the door bottoms.
• Supercharger Valley Hose: Located underneath is a coolant hose that can fail. While it is very cheap to find a replacement the process involves completely disassembling the supercharger system.
• Heater Core: These have a tendency to leak. Luckily the North American left-hand drive models allow for an easy replacement.
• TPS Sensor: The throttle position sensors tend to go bad any time after 50k miles. They are shared across the Jaguar line so picking up a used one should be easy.
• Driveshaft Center Bearings: The XJ uses a 2-piece driveshaft with a center bearing. These bearings can begin to tear after some time. This can be diagnosed by a clunk when placing the car into drive. Replacements are readily available.
• BBS Wheels: The factory BBS wheels have a tendency to bend, so potholes should be avoided.
• Brake Rotors: The OEM Brembo Rotors and Pads get chewed up regularly. It is best to go with a quality aftermarket solution when doing the brakes.
• Headliners: Will sag… Can be easily removed and taken to an upholstery shop.
• Electrical Gremlins: Given the sophisticated level of electronics in the car, many small quirky electrical problems can be caused by a faulty charging system. Before driving yourself mad trying to hunt down an electrical gremlin make sure you have a high-quality battery and check the car’s ground straps (this is especially true considering the aluminium construction).
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