On 27 February 1967, Mercedes-Benz presented the 250 SL, which replaced the 230 SL that had been produced for four years. On the outside the new car, whose series production had already begun in December 1966, was indistinguishable from its predecessor. The changes concerned mainly the engine and the brake system. Both were taken, slightly modified, from the 250 SE (W 108 III). The M 129 III engine, its displacement enlarged by 200 cubic centimetres, had the same output as the 230 SL, 150 bhp (110 kW) at 5500 rpm, but 10 per cent more torque and a flatter torque curve. It was now provided with seven crankshaft bearings for smoother operation, and with an oil/water heat exchanger as well; only the future 280 SL would be fitted with an air/oil cooler. The 250 SL thus was appreciably more flexible in operation, but did not quite reach the previous model’s top speed owing to its higher weight. The 250 SL’s top speed with four-speed manual transmission was 195 km/h or 200 km/h depending on the final drive ratio (standard: 1:3.92; optional: 1:3.69; automatic transmission: 190 km/h or 195 km/h). With five-speed manual transmission it was available in only one variant (1:4.08), which reached 200 km/h.
The changes to the brake system included disc brakes on the rear wheels as well, larger brake discs at the front, and the fitting of a brake power regulator to prevent rear wheel overbraking. As an optional extra a differential lock was now available. A fuel tank capacity of 82 litres instead of the previous 65 permitted an extended cruising range. In addition to the three body versions known from the 230 SL, the 250 SL was available as an optional extra in a fourth version, a coupé with rear seat bench, which was shown for the first time in March 1967 at the Geneva Motor Show. In this so-called California version, the necessary space for the rear bench seat had been obtained by eliminating soft top and soft-top compartment. Since the soft top could not be retrofitted, this variant promised unspoilt driving pleasure only in dry regions or with mounted coupé roof.
Less than a year after the presentation of the 250 SL, after 5196 units had been built it was replaced by the 280 SL. Apart from the model plate it could only be distinguished from the two preceding models on the outside by the different wheel hub caps.