The W154 was created as a result of a rule change by the sports governing body AIACR, which limited supercharged engine capacities to 3000cc.

[2] For the 1938 season, Grand Prix racing's governing body AIACR moved from a formula limited by weight to one by engine capacity.

The bodywork of the W154 was aluminium, left unpainted like its predecessors, making it another of Mercedes' famed Silver Arrows.

The W154 made its debut in the opening race of the 1938 season, the non-championship Pau Grand Prix in April.

Despite leading, Caracciola was suffering from an old leg injury, and when he pitted for fuel he handed the car over to Lang.

Dreyfus took the lead and would not need to pit as his car's lower fuel consumption meant he could complete the race non-stop.

Lang's car developed a spark plug problem and finished the race in second place, nearly two minutes behind.

Lang took pole position, with von Brauchitsch second and Caracciola third, ahead of the two Auto Unions of Christian Kautz and Rudolf Hasse.

Lang had difficulties in a pit-stop and Caracciola's engine started firing on only eleven of its twelve cylinders.

At the start, Lang took the lead but on lap three his car's spark plugs oiled up and he had to make an emergency pit stop.

Shortly afterwards, team manager Alfred Neubauer brought Lang into the pits so that Walter Bäumer, a reserve driver for Mercedes-Benz, could take over.

Meanwhile, Caracciola had been struggling with abdominal pain and stopped on lap ten to allow Lang to take over his car.

For the Coppa Ciano, Caracciola was entered in an experimental car with a larger saddle tank and a shorter tail section.

Pole position went to Carlo Felice Trossi in a Maserati 8CTF, but he retired on lap eight with engine troubles.

Caracciola retired due to a punctured fuel tank, leaving von Brauchitsch to win from Lang.

During 1938, the rules for the Indianapolis 500 were modified to allow the European Grand Prix cars to compete, and in 1947, Lee entered his W154 with Duke Nalon as the driver.

Due to the engine being mounted at an angle, the rear cylinders filled up with fuel, breaking the conrods and one piston.

[11][13] Alfred Neubauer attended the 1949 race, in order to investigate the feasibility of a works Mercedes entry at Indianapolis.

Neubauer studied Lew Welch's Novi team, and based on the information he had gained, Mercedes attempted to adapt the W154 for oval racing.

The cars were entered for two races in Argentina that year and attained two second-place finishes, with Herrmann Lang, Karl Kling and home favorite Juan Manuel Fangio driving.