Mercedes-Benz W108

Mercedes-Benz W108/W109 at a glance

Between the Fintail and the S-Class

The W108 took over from the six-cylinder W111 Fintail saloon. Mercedes kept the 2,750 mm wheelbase but made the body 25 mm longer, 15 mm wider and 60 mm lower than the old 220 S, with a flatter roof, larger windows and an almost square grille. The fins disappeared. Under the new skin sat the passenger safety cell with front and rear crumple zones that Béla Barényi had developed for the Fintail, and the boot held 610 litres.

Mercedes split the range by suspension. The W108 code covered the cars on steel coil springs, beginning in 1965 with the 250 S, the fuel-injected 250 SE and the alloy-engined 300 SE. The W109 code went to the long-wheelbase 300 SEL, which had air suspension as standard and replaced the air-sprung W112 300 SE Fintail at the top of the range. In 1972 the W116 took over, and its successors are traced in our S-Class generations guide.

Air suspension and the long-wheelbase W109

The W109 used an engine-driven compressor that pumped air at 16 bar into a reservoir and kept the ride height constant whatever the load. A dashboard switch raised the body by about 5 cm for rough roads or ramps. The short W108 cars made do with coil springs, helped at the rear by a hydropneumatic compensating spring that limited sagging under load.

Both series kept a swing-axle rear end and power-assisted disc brakes on all four wheels, with a brake force limiter on the rear axle. The 4.5 and 6.3-litre V8 cars received ventilated discs. A four-speed manual gearbox was standard in Europe and a four-speed automatic was optional; from May 1969 buyers of the 2.8 and 3.0-litre sixes could also order a five-speed manual.

From six cylinders to V8: engines by year

The 1968 revision brought the 2.8-litre M 130 six, which replaced the 2.5-litre engines and the 3.0-litre alloy six, together with a diaphragm clutch and a new interior. The 280 S became the best seller with 93,666 cars, followed by 91,051 of the 280 SE. From 1969 the new M 116 V8 with Bosch D-Jetronic injection gave the 300 SEL 3.5 a top speed of 205 km/h with automatic transmission and a 0-100 km/h time of 9.0 seconds. For its last two seasons the V8 also went into the short 280 SE 3.5, while American buyers received the 4.5-litre M 117 with a three-speed torque-converter automatic.

The 300 SEL 6.3: Waxenberger's private project

In 1966 the engineer Erich Waxenberger fitted the 6.3-litre V8 of the Mercedes 600 into a six-cylinder 300 SEL as a private project, after a journalist had described Mercedes saloons as cars for elderly drivers. His boss Rudolf Uhlenhaut drove it and approved the idea. Series production began in December 1967, and the car was presented at the Geneva Motor Show in March 1968.

The 300 SEL 6.3 produced 184 kW (250 PS) at 4,000 rpm and about 500 Nm of torque. Mercedes quoted 6.5 seconds from 0 to 100 km/h and 27.1 seconds for the standing kilometre, and top speed was about 220 km/h. Air suspension, ventilated discs, power steering, power windows and central locking were standard, and the price was around DM 40,000. Fuel use ran from 14 to 24 l/100 km from a 105-litre tank. By September 1972, 6,526 had been built.

AMG later turned one into the "Rote Sau" (Red Sow), which finished second in the 1971 Spa 24 Hours with an engine enlarged to 6,834 cc and 315 kW (428 PS). The road car's role passed in 1975 to the 450 SEL 6.9 of the W116 series.

Mercedes-Benz W108 today: what to check when buying

Rust is the main enemy. Classic & Sports Car points to the area above the headlights, where filler often hides corrosion, and to the rear suspension mounts. The Mercedes-Benz Club of America adds the front frame rails and bumper supports, the floor pans, the wings and the sills. Rippled inner panels and uneven gaps suggest old accident damage.

On six-cylinder injection cars, the pump and its control parts are expensive to rebuild, and the V8s need checks on their high-pressure fuel lines, which owners now replace with ethanol-resistant hose. A neglected timing chain on a V8 can stretch and damage the engine. Overheating usually means a silted radiator. On a W109, a healthy air system should hold the car level for about two weeks without the engine running; leaking valves, lines or air bags are costly to fix. The 6.3's differential wears under hard use, and the heater fan buried under the dashboard is a long job to replace.

Parts supply is good. Mercedes-Benz Classic supplies about 2,100 original parts for the range, and the factory can provide most panels and about 90% of the chrome. In Britain the Mercedes-Benz Club runs a W108/9 Register.

Values have moved apart by model. In July 2024 Classic & Sports Car gave average prices of about EUR 17,500 (GBP 15,000) for a 250 or 280, about EUR 23,500 (GBP 20,000) for a 280 SE 3.5 and about EUR 47,000 (GBP 40,000) for a 300 SEL 6.3, with show cars of the 6.3 up to about EUR 117,000 (GBP 100,000). In August 2025 automobile.at put a 280 SE 3.5 in condition 2 above EUR 30,000 and said the best 6.3s regularly pass EUR 90,000. More Mercedes models of the period appear in our Mercedes-Benz catalogue and the classic cars section. Placed between the Fintail and the W116, the W108 and W109 cover seven years of the larger saloons described in our history of Mercedes-Benz.