1975-1980 Mercedes-Benz 450SEL 6.9 | Old Model Sedan | Car Review

The 1975-1980 Mercedes-Benz 450SEL 6.9 was a continuation of the big-engine S-class sedan, now built on the W116 platform introduced for 1973. Considerably changed from its 6.3 predecessor, it featured somewhat lower and sleeker lines that were still distinctly Mercedes.

A bore increase brought up displacement on the big quad-cam V-8 engine, still related to the original 600 limousine unit, and there were numerous modifications such as Bosch K-Jetronic fuel injection, breakerless electronic ignition, dry-sump lubrication, and hydraulic valve gear actuation.



The suspension was shared with lesser-powered S-class models (lower A-arms, upper transverse links, and anti-roll bar in front; semi-trailing arms and anti-roll bar at the rear), but springing was now provided by hydropneumatic oil/nitrogen struts instead of air bags as on the 6.3.

As before, rear end self-leveling was incorporated to compensate for a heavy load of luggage or passengers. The revised chassis gave even better handling and roadholding than the already capable 6.3, plus a softer ride. Equipped with most every conceivable luxury feature, the 6.9 was slightly slower than the 6.3 off the line, but had a bit more available in top speed, now about 140 mph.

It came only with a three-speed torque-converter automatic transmission, which replaced the previous four-speed fluid-coupling unit. Fast but thirsty, the 6.9 was launched a good three years after the rest of the W116 range because of Mercedes' sense of propriety in the wake of the 1973-1974 Arab oil embargo.

When fuel prices "destabilized" again in 1979, U.S. fuel economy standards were in force, which made the 6.9 something of a liability here. Accordingly, the model was dropped after 1979. Still, this was the fastest version of what was widely considered "the best sedan in the world," argument enough for its status as a collectible.

Pluses of the 1975-1980 Mercedes-Benz 450SEL 6.9

• Prestige with punch
• Four-door convenience
• Superlative construction quality
• Rarity
• Greater refinement
• Better ride and handling

Minuses of the 1975-1980 Mercedes-Benz 450SEL 6.9

• Air suspension leak problems
• Thirsty
• Some mechanical parts in short supply
• U.S. versions more affected by desmogging and bumper rules than corresponding 6.3s
• Very pricey and likely to remain so

Production of the 1975-1980 Mercedes-Benz 450SEL 6.9

• 1,816 (U.S. sales include European deliveries)

Specifications of the 1975-1980 Mercedes-Benz 450SEL 6.9

• Wheelbase, inches: 116.5
• Length, inches: 205.5
• Weight, pounds: Approximately 4,500Price, new: $35,000 U.S. in 1976; $50,000 in 1979

Engines for the 1975-1980 Mercedes-Benz 450SEL 6.9

• Type: dohc V-8
• Size: 6,834 cc (417 cid)
• Horsepower: 250
• Years: 1975-1980