The Jaguar XJ model received its most extensive series of updates in 1979 and the result was the Jaguar XJ Series 3. A restyle done by car design firm Pininfarina saw the roofline raised slightly at the rear to create more passenger headroom. The front quarter light was deleted creating a one-piece front door glass. New flush fitting door handles were introduced, the rear lamps were updated and new rubber/chrome bumpers fitted. The Series 3 saw the option of an electric sunroof and cruise control introduced for the first time on an XJ model.
There were three engine options - the 5.3 litre V12 and the 4.2 litre straight-six, both featuring Bosch electronic fuel injection, and the carburetted 3.4 litre straight-six. The V12 was modified in September 1979 receiving a new "Fireball" high-compression cylinder head developed by Swiss engineer, Michael May. This improved fuel economy by 25% and the 5.3 litre V12 models were from this time onwards upto 1985 badged as XJ12 HE - HE referring to the High Efficiency engine. The transmission featured a five-speed manual gearbox, replacing the previous four-speed gearbox, and a three-speed automatic gearbox.
The last XJ model with a six-cylinder engine was produced in 1987. From then onwards production of the Series 3 continued with the V12 engine until November 1992 when production ended. The Series 3 production count stood at 132,952 units built, 10,500 of these with the V12 engine. In total there were around 318,000 XJ6 and XJ12 Jaguars produced between 1968 and 1992.