The scoring values of American diesel fuel is too high for the Bosch injection pump specs. So by adding 2 stroke oil during ea. fill you lower the scoring and increase lubricity to the level accepted by Bosch. 2 stroke oil has been tested for its score value and is near the top of the list for lubricity adjustment. Optilube had the best test results but, TCW 3 did well also. Using 2 stroke oil with its typical low ash content will keep injectors clean. Never use dieselKleen nor any solvent type. You need to have good filtration instead with a primary filter and then the factory filter is good as the secondary filter.
