BUYERS GUIDE Top of the Line – W186, W188 & W189 Sedans, Coupes & Cabriolets • 1951-1962

Richard Simonds, Gary Anderson

BG 300 01_1.jpgThe discrete, desirable and largely handbuilt Mercedes-Benz 300 series was a true top-of-the-market successor to the company’s storied ‘Grand Mercedes’ vehicles of the 1930s




Top of the Line – W186, W188 & W189 Sedans, Coupes & Cabriolets • 1951-1962


The discrete, desirable and largely handbuilt Mercedes-Benz 300 series was a true top-of-the-market successor to the company’s storied ‘Grand Mercedes’ vehicles of the 1930s


Article: Richard Simonds, Gary Anderson

Data Tables: Daniel Stahl 

Images: Maurice lIang  •  Daimler Archives

With German industry in shambles at the end of World War II, the management of Daimler-Benz aspired to regain the glory of the 1930s, when Mercedes-Benz vehicles were at the forefront of elegance and engineering. To achieve this lofty goal, the firm planned and executed a multi-pronged strategy to rebuild its enviable prewar strength and reputation. The company first built basic 170 utility vehicles and small sedans to replenish financial reserves before using that foundation to create an extraordinary series of sedans, coupes and cabriolets to reclaim its position as a world leader in luxury.


The return of elegance

At the Frankfurt Auto Show in April 1951, Daimler-Benz introduced a limited range of four-door sedans built around the company’s new 3-liter engine – vehicles thus designated as 300s. These stately machines offered tall grilles and voluptuous curves that recalled the automobiles of the late 1930s and early 1940s.

The 300 offered a 6-cylinder engine with overhead cam and two carburetors, 4-speed column-shifted manual transmission, and load-leveling rear axle, plus a massive X-frame, 12-volt electrical system and a central lubrication for the front suspension. Beautiful interiors rich with wood, Wilton carpets and high-quality fabric or leather upholstery created a sense of traditional luxury. The fledgling Federal Republic of Germany soon adopted a stretched version of the 300 as a state vehicle for the country’s first chancellor, Konrad Adenauer: The spacious interior allowed him to wear his top hat in the car – giving the 300 its enduring nickname, the “Adenauer.”

The 300b added a brake booster, front-door vent windows, two double-barreled carburetors and higher compression for more power. The 300c received a Borg-Warner automatic transmission and a larger rear window in 1955. In 1957, the 300d was completely restyled, had a longer wheelbase and a fuel-injected engine.

The Adenauer was available as both sedan and cabriolet. The cabriolet offered a soft top with Landau bars that folded back but did not fully retract to the body line. The rearview mirror was on a shaft that could be pivoted up to see above the convertible top when it was folded down. Though popular as parade cars for dignitaries, only a very small number of these four-door cabriolets were built.

The 300 sedans also were the basis for development of one of Mercedes-Benz’s most famous models, the 300SL Gullwing. By June 1951, believing its reputation would benefit from a return to international motorsports in Grand Prix and sports-car racing, management undertook the development of a racecar based on the block and head of the 300 engine. The 2,996cc engine block was canted at 45-degrees to fit in the low, space-frame body of the 300SL. Transmission, suspension components, and many interior elements were lifted straight from the parts’ bin of the 300-series sedans. The W194 300SLs – in coupe, roadster, and open-wheel form – would capture victory after victory all over the world, underlining the superiority of German engineering and reliability.


Adding sporty performance

The final prong of the company’s reputation-rebuilding strategy was introduced at the Paris Motor Show in October 1951. The 300S was a two-door grand touring automobile with coupe, cabriolet and roadster styles. This new range targeted entertainment celebrities and wealthy trendsetters just beginning to show off their affluence in postwar Europe and America; it was available only by custom order. Designated as the W188 with a wheelbase nearly six inches shorter than the Adenauer, this automobile used the 300 head and block, but with three carburetors, producing 150 horsepower. The 300Sc of 1956-1957 added chrome accents and a fuel-injected engine.

All three body styles were sketched by Hermann Ahrens, designer of the grand prewar 540Ks. Rather than drawing on the futuristic aero style popularized by American designers, Ahrens echoed key features of the 540Ks – a tall proud grille topped with the Mercedes star, curvaceous front fenders and a long hood line with short rear deck to visually thrust the car forward with a sense of presence and class. The 300S and 300Sc cabriolets were similar to the four-door 300 cabriolets. The 300S and 300Sc roadster had a fully retracting soft top that fit under a taut tonneau cover level with the body.

The interiors of these impressive two-door vehicles displayed meticulous design, fabrication and assembly. Wood veneer in a rich variety of grains and finishes was available, and soft trim was of the finest leather and woven wool. Luxury details included rear seats that folded down for luggage and a rear-view mirror that, like that of the 300d cabriolet, could be pivoted upward for visibility over the folded cabriolet top. A Grundig or Becker Nürnberg radio was standard, complete with two large speakers mounted in the foot wells. A set of fitted leather luggage for the trunk was available, as well as a set that fitted behind the front seats. Although many owners requested the fitted trunk luggage, the interior set is extraordinarily rare.

The impressive trio of personal luxury two-door models on the Paris show stand excited the crowds. Orders quickly flooded in; production was at capacity through 1952 and 1953. However, demand for such perfection wasn’t infinite, even in the burgeoning economies of the 1950s. Only 92 examples of the exclusive 300S left the Sindelfingen coachworks in 1954-1955. The revamped 300Sc appeared in 1956-1957 before the series was canceled.

When new, the sedans cost more than the famed 300SLs and the two-door models. However, the latter cars today command substantially more than the four-door sedans and cabriolets.

Given the styling and engine choices that were available to luxury buyers in the United States, Mercedes-Benz had to make changes in its luxury models. After all, a customer could buy a longer, lower, wider Cadillac or Lincoln with a V-8 engine, automatic transmission and air-conditioning for half the price of a top-of-the-line Mercedes-Benz sedan. Still, with their traditional elegance, the 300s were often purchased by wealthy people who did not want the ostentation that came with a Rolls Royce, Cadillac or Lincoln.


Reasons to buy a 300-series

Any of the 300s offer grand touring in luxury, elegance and style, often earning thumbs-ups from other drivers when cruising down the highway. Exclusiveness means the driver will be noticed – particularly in the four-door cabriolet and two-door models – when arriving at a car show.

Both two-door and four-door vehicles are very durable, with design features that were unusual for their time, such as a front lubrication system, rear load-leveling mechanism, four-wheel independent suspension and a 12v electrical system.

Sedans offer room for six occupants (with three in front) or room for five in luxury. The coupes, cabriolets, and roadsters are quite comfortable for four occupants. Every model in the 300 range offers grand touring with classic luxury, elegance and style.


Reasons not to buy a 300 series

If the car in question has not been well maintained, it can become a money pit. Replacement parts are difficult to find due to the low volume of original production. Restoration can be very expensive and exceed market value.

These automobiles offer very leisurely performance – even for the 1950s. In traffic, the heavy clutch and manual transmission can make driving laborious. The Borg-Warner automatic transmission does not match the torque curves of the engine and is expensive to repair; it can be replaced by a more modern transmission if total originality is not a concern.



Keep in mind that these cars are about 60-70 years old, and were assembled to order and produced only in limited numbers. Finding a completely original example is very important. Each unit was essentially hand-made; coupes, cabriolets and roadsters were custom-built and hand finished to a very high level of perfection. Consequently, body parts are not directly interchangeable.

Structurally, the biggest risk for the potential purchaser is rust that can be found in the box frame of the body-on-frame construction and around headlights, door drains and doorsills. A practical buyer should think carefully before undertaking an extensive restoration of one of these imposing cars; costs can quickly exceed market value many times over. Such a heroic effort may be worthwhile as a labor of love, but as an investment, it rarely pays off.

Carburetors are prone to warping and internal corrosion; balancing the two- and three-carburetor models is as much an art as it is science, and best done by someone with experience. Fuel-injection systems are subject to fuel deposits that make the vehicle run rough – or not at all. This is true of all cars with carburetors or fuel injection when they are not used regularly.

Electrical systems on unrestored cars likely will need replacement wiring and new relays and switches. Interior parts can be very expensive and difficult to find. Original tube-type radios are costly to replace, but can be rebuilt for a fee.

Suspension components are not readily available and expensive to replace or rebuild. If not lubricated regularly, the grease hardens and can cause suspension breakage.



Despite the complexity of these rare vehicles and the multiple challenges to restoring and maintaining them properly, W186, W188 and W189 300s change hands at very high prices, although significantly lower than the sports cars that share the same basic engine. Buyers who are able to afford one of these marvelous machines – and those of us who cannot – can not help but admire these fine automobiles that played such a key historic role in Mercedes-Benz regaining its reputation and status in the 1950s.

1952 W186 300 Sedan


1958 W188 II 300Sc Roadster


1958 W188 II 300Sc Coupe


1958 W188 II 300Sc Cabriolet


1958 W186 300c Cabriolet D






German Chancellor Konrad Adenauer (in office 1949-1963) used a 300 limousine; this example is on display at the national museum of German history in Bonn, the Haus der Geschichte.



1951    April                300 (W186) 4-door sedan revealed at first postwar Frankfurt international Auto Show


1951    October          300S (W188) 2-door introduced as roadster, cabriolet and coupe at Paris Motor Show


1951    November      300 sedan production starts, with 4-speed transmission (most column shift), two single-barrel carburetors, rear load levelers, front suspension lubrication, low-compression engines (6.4:1 for poor postwar fuels)


1952    March 300 cabriolet added


1952    June    300S cabriolet production starts


1952    August            300S coupe production starts


1952    September    300S roadster production starts


1954    March Recirculating-ball steering replaces worm steering in all models


1954    April   300 sedan and cabriolet production ends 


1954    May     300b sedan introduced, higher compression engines (7.4:1),

                        two double-barrel carburetors, brake booster, front vent windows,

                        rear door wind deflectors; 300b cabriolet added


1955    June    300S roadster production ends


1955    July     300S cabriolet production ends


1955    August            300b sedan, 300S coupe production ends


1955    September    300c production starts as improved sedan with larger rear window, available Borg-Warner 3-speed automatic transmission, larger tires


1955    December      300c cabriolet added. 300Sc coupe cabriolet, roadster production starts with chrome trim around the wheel arches & side of engine, and fuel-injection (“Einspritzmotor”) badge on rear bumper

1956    May                300c with 4 inch longer wheelbase introduced

1956    June               s300c cabriolet production ends



1957    July                 300c sedan production ends – all versions


1957    August              300d sedan is a redesign with 4-inch-longer wheelbase of 300c, pillarless hardtop construction, larger trunk, more vertical front and rear fenders and taillights, fuel injection, higher-compression ratio engine, and a Borg-Warner 3-speed  automatic transmission; manual transmission optional


1958    April                   300Sc coupe, cabriolet and roadster production ends


1958    July                    300d cabriolet production starts


1958    December          Optional Behr air conditioning offered for 300d, a first  for Mercedes-Benz


1962    February            300d cabriolet production ends


1962                              March 300d sedan production ends


Notes: Most 300c and nearly all 300d models sold in the United States had automatic transmissions. All postwar Mercedes-Benz engines have hardened valve seats and valves, allowing them to be operated with unleaded fuel. The 300, 300b and 300c can be operated on regular fuel; the higher-compression 300d requires premium fuel.



MODEL                YEARS         CHASSIS         ENGINE           POWER (DIN hp)       TORQUE (DIN lb-ft)               

300 Sedan         1951-1954        186.000           2,996cc I6        115 at 4,600                    145 at 2,500                                            

Cabriolet D        1952-1954       186.014                                                      

300S Coupe       1952-195         188.011            2,996cc I6         150 at 5,000                 170 at 3,800                                            

Cabriolet A         1952-1955      188.000                        

Roadster            1952-1955       188.012                                 

300b Sedan        1954-1955      186.011             2,996cc  I6        125 at 4,500                163 at 2,600                                            

Cabriolet D         1954-1955      186.014                        

300c Sedan         1955-1957      186.016            2,996cc  I6         125 at 4,500                163 at 2,600                                            

Cabriolet D         1955-1956      186.033                                                       

300Sc Coupe      1955-1958      188.014            2,996cc I6           175 at 5,400               188 at 4,300                                            

Cabriolet A          1956-1957      188.013                 

Roadster              1956-1958      188.015                                                                                          

300d Sedan          1957-1962      189.010            2,996cc               160 at 5,300              175 at 4,200                                            

Cabriolet D           1958-1962      189.033          


MODEL                              TRANSMISSION      0-62 MPH            TOP SPEED                 MPG (US)

300 Sedan                                 M-4                      18 sec.                      96                             14.3

Cabriolet D                                                                       

300S Coupe                              M-4                      15 sec.                     109                             13.8

Cabriolet A                            


300b Sedan                               M-4                      17 sec.                      99                              14.7

Cabriolet D                                                                       

300c Sedan                           A-3 • M-4               17-18 sec.                 96-99                      13.8-14.7

Cabriolet D                                                                       

300Sc Coupe                             M-4                     14 sec.                      112                           13.8

Cabriolet A                             


300d Sedan                            A-3 • M-4              17-18 sec.                103-106                    13-13.8

Cabriolet D                            



Production Totals

YEARS             MODEL                                               TOTAL BUILT

1951-1954       300 Sedan • Cabriolet                             4,927

1951-1955       300S Coupe • Cabriolet • Roadster           560

1954-1955       300b Sedan • Cabriolet                           1,878

1955-1957       300c Sedan • Cabriolet                           1,483

1955-1958       300Sc Coupe • Cabriolet • Roadster         20