• 1 March: Colonel Adolf von Schell, Executive for Motorised Transport, presents a plan to reorganise the German motor vehicle model programme. The aim is to reduce the number of models sharply and distribute them among individual manufacturers. The Schell Programme, adopted by decree on 2 March, reduces the number of car models from 52 to 30 and the number of truck models from 133 to 21. It is to take effect on 1 January 1940.
• 5 September: Upon the outbreak of the Second World War, the Schell Programme is replaced by a new wartime programme designed to further reduce the model range of the German motor vehicle industry. It cuts the number of car models to five; they include the Mercedes-Benz 170 V. The 3-tonne and the 4.5-tonne vehicles from Daimler-Benz production are declared strategically important trucks.
• October: Car production ceases at the Mannheim plant. Production of the Mercedes-Benz 500 N is completely discontinued, while construction of the 320 model is concentrated in Untertürkheim. The Mannheim plant is thereafter assigned exclusively to building commercial vehicles.

(Motor und Sport, October 1938)

In February the International Motor and Motorcycle Show in Berlin saw the launch of a new 230 with the internal code W 153. Although it has the same engine as the W 143, the chassis and bodies are completely new. The W 153 is replacing the two-seater and four-/five‑seater variants of the W 143, while the six-/seven‑seater versions in the form of pullman saloon, pullman landaulet and open tourer remains in production.
The engine has some detailed improvements to address the deteriorating quality of petrol. The compression is reduced to enable the engine to remain fully operational even when run on 74 octane fuel. To compensate for the loss of power, the combustion chambers are modified, while 60 ccm is added to the displacement by widening the bore. The intake manifold is now automatically heated by means of a bimetallic heating element.
The front and rear axles on the W 153 are broadly the same as on the W 143 but the chassis is completely new. Although the 3050 mm wheelbase is retained positive experience with the X-shaped oval tubular frame on the 170 V is now applied by chief designer Max Wagner to a larger model.
The body is also completely new. Daimler-Benz for the first time opted for the all-steel body rather than traditional wood-and-metal construction. The all new instrument panel is now much more clearly laid out than on the predecessor. The instruments are no longer in the centre, but positioned directly in front of the driver. A cooling water remote thermometer is provided as standard. The optionally available radio is integrated into the centre of the dashboard, while there is a large closed glove compartment on the right-hand side. The introduction of the pistol-grip hand brake give more room in the front footwell. Two adjustable air flaps allows fresh air to enter the ventilation box, which is mounted outside in front of the windscreen, from where the air flows without draught through air vents underneath the windscreen into the vehicle interior. Rear pop-out windows ensures efficient ventilation. A heater is available for an extra RM 110. The W 153 is the first Mercedes-Benz to feature an alligator hood that could be opened from the inside. The rear-mounted fuel tank has a capacity of 52 litres, 2 litres more than in the previous model. On the saloon, the radio antenna is in the centre of the roof above the windscreen and could be erected from inside. The convertibles has a ribbon antenna sewn into the soft top.
The range comprises the four-door saloon, optionally with sliding roof, and the Convertibles A, B and D.

230 (W 143) Cabriolet C

230 (W 143) Tourenwagen

230 (W 143) Limousine
(Motor und Sport, October 1938)

230 (W 153) Limousine

230 (W 153) Cabriolet A

230 (W 153) Limousine

230 (W 153) Cabriolet B

230 / 260 D

230 / 260 D Landaulet

320 Pullman-Limousine

Despite the highly pleasing lines of its bodies, the 320 N (short wheel-base) was no longer included in the price list of February 1939.
Early this year the 3300 mm wheelbase variants underwent modification. The engine displacement is increased to 3405 cc by adding 2.5 mm to the bore, mainly to avoid having to reduce the power output in view of a deterioration in petrol quality. The model designation 320 as well as the design codes W 142 and M 142 are retained. In view of the growing use of autobahns, the 320 is now provided as standard with an additional ZF cruising gear. This consists of a planetary gear behind the normal four-speed transmission, which reduces the engine speed by 25%. This autobahn cruising gear can be engaged using a separate lever. A cooling water remote thermometer is added to the standard equipment package. There are also innovations on the body front: the saloon with streamlined body is no longer offered and the pullman saloon is provided with a so-called "add-on trunk" instead of the integrated luggage rack. The add-on trunk is a permanently mounted luggage compartment organically joined to the rear of the body. The Convertible D feature a slightly revised design with a wedge-shaped, split windscreen.
The Kübelwagen come with the standard four-speed transmission without cruising gear. To compensate for the 20‑inch wheels with off-road tyres, the first two gears and the final drive are significantly lower-geared than on the standard production vehicles.

In February 1939, the 540 K and the "Grand Mercedes" were made available with a five-speed transmission that reduced the revolutions in fifth gear by 20% in comparison with fourth gear.
Between February 1934 and November 1939, the Untertürkheim plant produced a total of 761 chassis of the two W 29 models, 342 with five-litre displacement and 419 with 5.4-litre versions. Seventy chassis were supplied to specialist coachbuilders, while the other 691 units were fitted with bodies at the special vehicle production facility in Sindelfingen. The top-seller was the convertible B with 296 units, followed by the Convertible C and Convertible A with 122 and 116 vehicles, respectively. Even the exclusive Special Roadster had a total production run of around 50 units, whereas only 12 of the various coupé variants were manufactured, with as few as just six buyers being found for the Autobahn-Kourier. The statistics were rounded off by 53 saloons and 28 open tourers.
In 1939, experimental 5.7-litre engines were built based on the M 24. These engines had a 7 mm wider bore, but 5 mm shorter stroke than the 5.4‑l itre unit.

540 K Spezial-Roadster

540 K Cabriolet A kurz

770 Cabriolet D

770 Cabriolet B

Other Victories:

1st GP Pau (Lang)
1st Eifelrennen (Lang)
3rd Eifelrennen (Caracciola)
1st GP Tripoli W165 (Lang)
2nd GP Tripoli W165 (Caracciola)

• February 8/9/14: On the Reichsautobahn near Dessau Rudolf Caracciola, at the wheel of the 3 liter record car, sets several new records, including, on February 9, 399.6 km/h for the mile with flying start.
• 8 April: At the Pau Grand Prix in France, the first outing for the 3-litre formula racing car revised and equipped for the 1939 season with the new M 163 engine, Mercedes-Benz posts a double victory with Hermann Lang and Manfred von Brauchitsch.
• May 7: Hermann Lang and Rudolf Caracciola occupy the top two places in the first and only race contested by the 1.5 liter W 165 formula racing car in Tripoli.
• 21 May: Hermann Lang wins the International Eifel Race on the Nürburgring.
• 11 June: Hermann Lang wins the Vienna Höhenstrasse mountain road race in a Mercedes-Benz W 154 hillclimb car.
• 25 June: Victory at Belgian Grand Prix.
• August 6: Hermann Lang wins the German Mountain Grand Prix on the Grossglockner Pass in a W 125 hillclimb car to be crowned "Pan-German Hillclimb champion" of the 1939 season.
• 20 August: The Swiss Grand Prix at the Bremgarten circuit near Bern ends in a triple triumph: Hermann Lang wins, followed by Rudolf Caracciola and Manfred von Brauchitsch, ending the season as the most successful driver.
• September: Hermann Lang becomes European Champion and German Hill-Climb Champion and Rudolf Caracciola German Road Champion.
• 12 October: The Mercedes-Benz T 80 completes its first run on a chassis dynamometre. The three-axle record-breaking car, inspired by Hans Stuck in 1936 and designed by Ferdinand Porsche, is powered by a DB 603 V12 aeroengine. The Second World War prevents its development to operational readiness.
• The 3 liter W 154 Formula racing car takes five victories from six first class races: First and second places in the Pau Grand Prix, (April 8) first, third and fourth places in the International Eifel Race (May 21) first and third places in the Belgian Grand Prix (June 25) first place in the German Grand Prix (July 23) and first, second and third places in the Swiss Grand Prix (August 20).

This is 1939 W 154 at IAA in Berlin.

W 163 Mercedes-Benz fitted with a 3-litre V12 type M 163 engine developing 485 h.p. This fine action shot shows Lang near Gueux on the Rheims circuit, for which he holds the lap record at 117.5 m.p.h. in practice, and 114.86 m.p.h. in a race.

GP Pau

Hermann Lang's racing car (start number 181) was fitted with twin tires at the rear to improve traction. He took first place in the Vienna Höhenstrasse mountain road race.
 

1.5 litre, twin supercharged W 163 at Tripoli GP.

Triple victory at the Swiss Grand Prix, August 20, 1939. The winner Hermann Lang (start number 16) during the race in a Mercedes-Benz W 154. Second place: Rudolf Caracciola. Third place: Manfred von Brauchitsch.

Mercedes-Benz T 80

The off-road sports cars based on the 170 V posted a string of victories between 1937 and 1939. All versions combined reached production volume of around 30 vehicles.

the competition vehicles based on the W 153. These were two-seater open sports cars with in-house designations 230 SV and 230 S. The 2700 mm wheelbase was the same as in for the short 230 N version of 1937. Bodies of magnesium alloy and wings of sheet aluminium made them extremely light. They were successfully used in 1938 and 1939 in the then highly popular off-road events. While 33 units of the 230 SV were produced in 1938, 21 units of the 230 S were built in the following year, of which 19 were roadsters and two were two-door fastback sports saloons. The difference between the two versions lay in the engines. Whereas the 230 SV still had the M 143 with 2229 ccm displacement, the 230 S was powered by the M 153, which had been rebored to 2289 ccm. Both engine variants had a higher compression than in the respective standard-production units and also a slightly higher power output of 58 hp.