The Mercedes-Benz W180 is an inline 6-cylinder saloon, coupé, and convertible produced by Mercedes-Benz from 1954 until 1959. The models associated with the W180 chassis code were the 220 a and, later, the 220 S

See Mercedes-Benz S-Class for a complete overview of all S-Class models.

The W180 was one in a range of Mercedes-Benz models to informally receive the "Ponton" nickname. This was in reference to the unibody-type, pontoon-shaped exterior styling which was also featured on the later W128 line.

Introduced in March 1954, the 220 a was a more luxurious and up-scale version of the W120 model 180 with a wheelbase stretched by 170 mm (6.7 in). 100 mm (3.9 in) of that increase in length was necessary to accommodate the longer straight-six, M180 engine. The passenger cabin was lengthened by 70 mm (2.8 in) to increase the legroom available to rear-seat passengers, while the boot remained unchanged. From the side, these six-cylinder cars can readily be distinguished from their shorter four-cylinder siblings by the extra "quarter light" windows incorporated in the rear doors.

The engine was carried over from the W187 model 220; in this application it was fed by a single carburetor and delivered 85 PS (63 kW; 84 hp). Production of the 220 a ended in April 1956, with 25,937 units produced.

The 220 a was succeeded in March 1956 by the 220 S, which was externally almost identical, but had an upgraded version of the 2.2L inline-six (100 PS (74 kW; 99 hp), later 106 PS (78 kW; 105 hp)), due to the use of twin-carburetors.

Visually, the 220 S featured a new one piece front bumper, instead of the 3-piece bumper used on the 220 a. Also, the twin chrome and rubber strips running under the doors of the 220 a were replaced with solid chrome strips. The most obvious difference is the addition of a chrome strip running along the front fenders and doors of the 220 S.

The 220 S was available with a 4-speed column shift manual transmission, with an optional Hydrak automatic clutch. This made use of small microswitches on the gear selector that automatically disengaged the clutch when the driver changed gears. Many cars have subsequently been converted to use a regular manual clutch, due to the high maintenance costs of continuing to use the Hydrak clutch.

Also introduced with the 220 S was the W105 219, which from the a-pillar forward was essentially a single-carburettor 220 a, but rearward from the a-pillar it used the shorter body of the W120/W121 180/190 models.

In July 1956, a convertible (two doors, four seats) joined the line-up, and in October 1956 a coupé version followed suit. Some convertibles were finished with folding rear seats to accommodate additional luggage.

Until October 1959, 55,279 220 S saloons and 3,429 convertibles and coupés were built.

The fuel-injected 220 SE versions that officially bore the model code W128 were introduced in October 1958 and carried on until November 1960.^[4]

• 1959 Mercedes-Benz 220 S saloon (W180)
• 1957 Mercedes-Benz 220 S Coupe
• Mercedes-Benz 220 S Convertible (W180)
• Mercedes-Benz 220 S Convertible interior (W180)