Start of production suddenly recedes into the distance

The supply situation in 1947 for coal, electricity and gas was calamitous, however. The first test vehicle was assembled at the beginning of that year, but the start of production, originally scheduled for July 1948, now receded far into the distance. Opel extended the contract until 1949, which suited the designers just fine, because it allowed them to subject both the L 3250 and the OM 312 to more thorough testing. For one thing was clear – the new design simply had to succeed.

Wilhelm Haspel was very conscious of the risks involved, particularly with the OM 312. At the end of 1947, he warned: “… The approach to this engine in terms of testing has not been as circumstances should have dictated.” The developers used the additional time to put the engine design on a solid footing.

Enthusiastic reception for the L 3250

When the engine was first unveiled to the public in May 1949 at the export fair in Hanover, it caused a sensation in the truck sector – a diesel unit with the same power per litre as a petrol engine. Moreover, in the shape of the L 3250 they were looking at a diesel truck with virtually the power-to-weight ratio of a petrol truck. Nevertheless, the OM 312 did have certain idiosyncrasies: since the right-hand side had an open design similar to the Opel engine and was sealed only with a cap, it lacked something in terms of rigidity. Cracks in the relatively weak connecting rods were not infrequent.

The L 3250: a diesel truck with the same power-to-weight ratio and temperament as a petrol engine.

In professional circles, the OM 312 was ecstatically received. In issue 9/1950 of the magazine Das Last-Auto, for example, vehicle tester Hans-Arnold König made the following comment: “What liveliness and power the engine has! This test driver has to admit that he was astonished at the incredible tractive power of this 4.6-litre engine.” The L 3250 brochure had similar praise for the engine qualities: “The newly designed six-cylinder diesel engine has a character such as was thought possible up to now only in high-speed passenger car petrol engines.”

All of this also generated international interest, which fitted well with Wilhelm Haspel’s efforts to kick-start exports. His principal focus was on the South American and Indian markets. In March 1949, for example, he wrote to his trusted friend Moritz Straus in Zurich, who had owned the Horch plants before the creation of Auto Union: “In particular, we have to tackle the South American market … and see what can be done there.”