3 - Intro to the XJ40 ( ,
The Jaguar XJ40 was the result of a 10 year design exercise with the Jaguar design department attempting to best the classic design of the first generation XJ6. The XJ40 prototypes began with a body design very similar to the final result, wandered through the boxy, angular shapes that were popular in the early-1980s, before returning to the body style that we know today as the XJ40.
While the XJ40 body design was simplified greatly over that of the series III XJ6, the XJ40 electrical system became much more complex.
The early 1987/ 88 XJ40 models were the least reliable, with electrical problems such as erratic gauges, starter and fuel pump failures being very common.
Metric tires: Early XJ40ís came with metric sized tires. The metric tires tend to be more expensive and come in fewer sizes than the more common standard sized tires.
The 1990-93 years were ideal years for reliability. Improvements were made to the power seat motors, improved sealing of the trunk (fewer leaks) and more improvements in the electrical system.
Things to really look for are oil leaks at the right front corner of the head and rear suspension problems. The oil leak tends to be the head gasket and can be quite a problem. Look for oil between the distributor and the head. The rear suspension should be converted to standard to get rid of the hydraulics.
Overall though, these cars have a very good record for keeping going, with most faults being annoying and easily fixed.
Beware. XJ40 odometers can be fiddled. One method is by reprogramming the instrument pack to any desired mileage with the use of a portable computer and some specialist software. Nothing particularly new in that idea; the unscrupulous have been doing it to other makes of cars for years. However, there is an easier way the mileage recorder can be changed. Some XJ40 odometers only display their sixth digit once you reach 100,000. If you know which joint to solder, the sixth digit can be disabled permanently, wiping 100,000 off the clock! So don't forget to check the service history.
The single cam 2.9 engine found in Europe should be avoided. It's a derivative of Jaguars legendary 5.3 V12 HE; but don't let that fool you. Limp-wristed, and comparatively thirsty, the other sixes are far better in every way. Driven hard, the 2.9 pulls well, but soon runs out of puff long before its top speed. Poor bottom end torque makes town driving tiresome. Timing chains are a real problem - just 20k can render chain rattle; then the head has to come off. Watch out for blue smoke on cold takeoffs, uneven idle, pinking under load, and hesitation on acceleration.