A new chapter in off-road models started in September 1989 when a completely reworked model range with the in-house code 463 series was launched. The main objectives of the facelift were compliance with ever increasing customer demands for greater comfort and a move away from austere utility vehicle to comfortable, multi-purpose car. As a result, the interior design of the new generation was based much more closely on that of passenger cars. This impression was reinforced by the understated style of the updated front section that was painted in body colour.
As well as the facelift, technical modifications were also carried out. The most notable was the modification to the drive train to increase ride comfort. Instead of manually selectable four-wheel drive, it now had permanent four-wheel drive and differential locks as standard. Customers buying off-road vehicles could now also benefit from the ABS anti-lock braking system that had proved highly effective in passenger-car models, and a version that could be disengaged became available. The engine range was also restructured. While the 2.5-litre diesel engine, the 2.3-litre injection engine and the 2.0-litre variant for Italy were already familiar components of the 460 series, and updated versions of them were now in use, two state-of-the-art, six-cylinder engines were deployed in off-road vehicles for the first time. They were the 3.0-litre OM 603 diesel engine and the M 103, which had petrol injection and the same 3.0-litre capacity. The petrol engines were fitted with a closed-loop emission control system as standard.
In line with the applications advertised, the series 463 off-road vehicles were no longer available as panel vans. Customers could choose from short-wheelbase open pick-ups, now known as Cabriolets, and two versions of the Station Wagon. The 460 series with all body variants was kept in the sales range for professional, commercial users and the tried-and-tested engine range was also retained, with the exception of the 2.8-litre petrol engine.
After being launched in the spring of 1990, the series 463 off-road vehicles were constantly fine tuned, with the most striking changes being to the engine range, as seen from the different model designations. The first model launched to meet demand for increased engine performance was the 350 GD Turbo, which was released in April 1992. Its 3.5-litre turbodiesel engine generated 136 hp and was combined with automatic transmission as standard. The 250 GD, the lowest-power model in the series, was dropped from the range. The 500 GE V8 with a 240 hp 5.0-litre V8 engine was at the opposite end of the performance scale, and it was produced in an exclusive, small-scale production run in 1993.
In September 1993, the G-Class model designations were aligned with the new system for naming passenger car models, with the 'G' now preceding a three-digit number and the 'E' and 'D' suffixes being dropped. At the end of 1993, the G 320 model was added to the range. Its 210 hp four-valve six cylinder engine was already familiar from S-Class and E-Class cars and, like the G 350 Turbodiesel, the new model was supplied with four-gear automatic transmission as standard. In July 1994, the G 230, G 300 and G 300 Diesel models were dropped from the sales range in Germany.
Around two years later in September 1996, the G 300 Turbodiesel was finally launched on the market as the replacement for the previous G 350 Turbodiesel. In contrast to its predecessor, the new diesel model had a turbocharged engine with four valves per cylinder and charge air cooling. Its output had been increased by more than 40 hp to 177 hp, it generated 10 percent more torque that was now available across a wide range of engine speeds, and its optimised combustion significantly reduced emissions and fuel consumption. It is also notable that the five-gear, electronic automatic gearbox was fitted in the G 300 Turbodiesel as standard; the new automatic gearbox was now lighter and more compact than comparable gearboxes with five gears and its slip-controlled torque converter lockup clutch also made it highly efficient.
Extensive facelifts were also carried out in 1997, the first being a new version of the Cabriolet with an electro-hydraulically operated soft top that was introduced in June following its premiere at the International Off-Road Vehicle Show in Munich in April. When the vehicle was unlocked, a single touch of a button could open or close the soft top in around 30 seconds. The new Cabriolet version could be identified by the additional triangular side plates behind the rollbar that covered the solid main bearing and complex soft-top kinematics as well as its smaller area of fabric to minimise wind noise.
There was then another model change six months later when the previous G 320's six-cylinder in-line engine was replaced by a completely new V6 engine with the same capacity that had been launched in the E-Class nine months before. Notable innovations were the three-valve technology with two intake valves and one outlet valve, and the phased, alternating dual ignition with two spark plugs per cylinder. The development of the new generation of engines focused on achieving a fuller torque curve and on cutting fuel consumption. Optimum power transmission was ensured by five-gear, automatic transmission with electronic control that was already familiar from the G 300 Turbodiesel. Other innovations to simplify maintenance included fitting disk brakes to the rear axles of the series 463 models as they had been on the 290 GD Turbodiesel. The G 320 was also given the ASSYST flexible maintenance system that uses an electronic maintenance monitor to calculate service dates based on the vehicle's actual use and operating conditions.
The G 500, a new top-of-the-range G-Class model, was unveiled to the public at the International Off-Road Vehicle Show in Munich in April 1998. Its 220 kw (300 hp) 5.0-litre V8 engine with three-valve technology and dual ignition delivered impressive torque of 440 Newton metres with spectacular performance. In addition to top engine specifications, the G 500 also boasted a wide range of standard equipment, including air conditioning, metallic paintwork, leather upholstery, electric seat adjustment, heated front seats and a cassette-radio. The top-of-the-range model also featured restyled 18-inch alloy wheels, chrome-effect crossbars in the radiator grill and V8 emblems on the sides of the vehicle. The glass covers on the front and side turn indicators were white, while the tail lights were bichromatic. The G 500 was launched on the market in June 1998.
