There are at least 3 ways to run a diesel motor on biofuel using vegetable oils, animal fats or both. All three are used with both fresh and secondhand oils.

1. Use the oil simply as it is-- generally called SVO fuel (straight vegetable oil);

2. Mix it with kerosene (paraffin) or petroleum diesel fuel, or with biodiesel, or blend it with a solvent, or with fuel;

3. Convert it to biodiesel.

The first 2 approaches sound most convenient, however, as so typically in life, it's not rather that simple.

1. Mixing it

Vegetable oil is much more viscous (thicker) than either petro-diesel or biodiesel. The function of blending it or blending it with other fuels is to reduce the viscosity to make it thinner so that it streams more easily through the fuel system into the combustion chamber.

If you're mixing veg-oil with petroleum diesel or kerosene (like # 1 diesel) you're still using fossilfuel-- cleaner than many, but still not clean enough, many would state. Still, for each gallon of

vegetable oil you use, that's one gallon of fossil-fuel conserved, which much less climate-changing carbon in the environment.

People use different mixes, varying from 10% vegetable oil and 90% petro-diesel to 90% veggie oil and 10% petro-diesel. Some individuals simply use it that way, begin up and go, without pre-heating it (which makes veg-oil much thinner), and even use pure grease without pre-heating it, which would make it much thinner.

You might get away with it with an older Mercedes 5-cylinder IDI diesel, which is a really difficult and tolerant motor-- it will not like it however you probably will not eliminate it. Otherwise, it's not wise.

To do it properly you'll need what amounts to an SVO system with fuel pre-heating anyway, ideally using pure petro-diesel or biodiesel for starts and stops. (See next.) In which case there's no requirement for the blends.

Blends with different solvents and/or with unleaded gas are "speculative at best", little or nothing is learnt about their results on the combustion characteristics of the fuel or their long-lasting impacts on the engine.

Higher viscosity is not the only problem with utilizing vegetable oil as fuel. Veg-oil has various chemical residential or commercial properties and combustion qualities from the petroleum diesel fuel for which diesel engines and their fuel systems are created.

Diesel engines are high-tech devices with really exact fuel requirements, specifically the more contemporary, cleaner-burning diesels (see The TDI-SVO debate).

They're hard but they'll only take a lot abuse. There's no warranty of it, however utilizing a mix of approximately 20% veg-oil of excellent quality is said to be safe enough for older diesels, especially in summertime.

Otherwise utilizing veg-oil fuel needs either a professional SVO solution or biodiesel. Mixes and blends are typically a poor compromise. But mixes do have an advantage in cold weather condition.

As with biodiesel, some kerosene or winterised petro-diesel fuel combined with straight veggie oil lowers the temperature at which it starts to gel. (See Using biodiesel in winter season) More about fuel blending and blends.