Key factors: 2T oil must be mineral (mixes with diesel better), low ash AND meet JASO FC specification.
From RAC forum:
Effects of 2t oil added to diesel cars.
Due to the pollution control measures of the EC diesel-oil is nearly sulphur free and contains up to 5% of bio-diesel. Sulphur has the property to grease the high pressure injection pump and the injectors. Without sulphur, the reduced greasing property of the new diesel has already shown negative impacts on the long-term stability of the injectors and the high pressure pump. The pump manufacturers have tried to react by lining the moving parts of the pumps with Teflon or other suitable material. However, the long term stability is still not achieved as with the old (sulphur contained) diesel.
The engine-research centre of a well-known German car manufacturer has conducted some long term tests of diesel additives to find out whether any one of them will have an impact on the long term reliability of the diesel engine components. This introduction to explain were my information comes from.
The results of this research: any diesel additive of any manufacturer presently on the market is not worth the money!
BUT: 2-stroke oil, which we use in our motor saws, lawn mower or in 2-stroke motor engines has shown to have an extreme positive impact on diesel engines, if such 2-stroke oil is added to the diesel in a homeopathic doses of 1:200. In practical terms: 0,300 litre of 2-stroke oil into the 70l diesel tank. The 2-stroke oil will be absorbed by the diesel (emulsion) and grease every moving part of the high pressure pump and the injectors.
Besides this, the 2-stroke oil will keep the diesel engine clean, as it burns cleaner as the diesel itself.
In other words, the 2-stroke oil has a much
lower ash-content as diesel, when burned. This proven fact delays the DPF (diesel particulate (soot) filter) to clog, and the "burn free" process of the DPF will be much less.
More information: in Germany we have to present our cars every 2 years to the TUV -Technical Supervision Organisation - who will check, amongst others, the pollution of petrol and diesel engines.
The measured cloud-factor of a diesel engine without use of 2-stroke oil has been 0,95.
The same factor with the use of 2-stroke oil has been 0,47 - reduction of nearly half of the soot particles.
Besides this, the use of 2-stroke oil in the diesel will increase the mileage by 3-5%.
