The Mercedes-Benz 170S is a luxury car which was produced by Mercedes-Benz from 1949 until 1955 in various gasoline and diesel powered forms. It was initially offered with a 1.8 liter version of the 1.7 liter inline-four cylinder M136 engine used in the slightly smaller production type 170 V. It was the first Mercedes-Benz to carry in its name the suffix “S” (for Sonder modell (Special model) denoting a superior level of comfort and quality. As such, its intended market was successful business owners and company directors.
The 170 S was released in May 1949, initially sharing the chassis number of the W136 170 V, and closely resembled it. However, in several respects it was more directly a development from the six cylinder Mercedes-Benz 230 which the company had produced, albeit in small numbers, between 1938 and 1943.
The first 170 S upgrade occurred in January 1952, being further distanced from the 170 V with its own chassis number W191. Mercedes' introduction a year earlier of the 2.2 liter six cylinder M180 engined Mercedes-Benz W187 luxury 220 model, positioned between the 170 S and the company flagship 3.0 liter Mercedes-Benz W186 Adenauer tourers undermined the four cylinder 170 S's luxury niche.
With the arrival of the all-new 1.8 liter Mercedes-Benz W120 180 "Ponton" in 1953 the 170 S was discontinued and a 170 S-V employing the 170 S' larger engine but the 170 V's slightly smaller body was introduced. It ceased production in 1955.