Mercedes-Benz W126 S-Class history: 1979–1992

W 126 S-Class history

The 126 series was developed for comfort, safety and lower energy use: lighter materials and a wind-tunnel-optimized body cut fuel consumption by 10% versus the 116 series. It also introduced the driver airbag with a front-passenger belt tensioner.

A revised range arrived at Frankfurt in September 1985 with new six-cylinder engines, a 4.2-liter V8 and a 5.6-liter V8 (272 hp, or 300 hp in non-catalyst ECE form). The 560 SEL and 560 SEC were then the most powerful Mercedes production cars ever built.

The US also got diesel S-Classes — the 300 SD turbodiesel and, from 1990, the 350 SDL — and most variants ended between August and October 1991, with the last armored cars in April 1992.[1],[2],[4]

Years and production numbers

Key variants

Engine and drivetrain facts

• The 560 SEL's 5.6-liter V8 came from lengthening the 5.0-liter's stroke; Mercedes-Benz Classic lists 272 hp (catalyst 242 hp) at launch and 300 hp (catalyst 279 hp) from September 1987.
• The 300 SD exported to the US used a turbocharged 3.0-liter five-cylinder with 125 hp.
• From April 1990 the 350 SDL with a 3.5-liter turbodiesel six was built for the US only.

Sources:[1],[2],[3]

What changed, year by year

1. 1979Saloon launch with all-aluminum V8s.
2. 1980sDriver airbag with front-passenger belt tensioner; front-passenger airbag optional from 1988.
3. 1985Facelift and new engines incl. 560 SEL.
4. 1991–1992Replaced by the W 140; last armored cars April 1992.

Sources:[1],[2],[4]

What to check before you buy one

• Check the timing chain and guides on V8s, and the self-leveling rear suspension on SEL models.
• Inspect for rust at the jacking points and rear window surround.
• On diesels, confirm the turbodiesel's service history.
• Compare against the S-Class known-issues list and confirm options with the build record.

Model-specific problems by generation are tracked on our Mercedes-Benz S-Class known issues page.

How to verify the factory options of any W 126 S-Class

For 1981-on W 126s, the factory data card by VIN lists paint, interior and the option codes — useful for confirming a 560 SEL's equipment or a US diesel's spec.

W 126s from model year 1981 on have 17-character VINs; 1979–1980 cars predate the standard.[5],[6]