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

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

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

3. Convert it to biodiesel.

The very first 2 techniques sound simplest, however, as so frequently in life, it's not rather that easy.

1. Mixing it

Vegetable oil is much more thick (thicker) than either petro-diesel or biodiesel. The function of mixing 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 blending veg-oil with petroleum diesel or kerosene (very same as # 1 diesel) you're still using fossilfuel-- cleaner than most, however still unclean enough, numerous would state. Still, for every gallon of

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

People use different mixes, varying from 10% grease and 90% petro-diesel to 90% grease and 10% petro-diesel. Some individuals just use it that way, start up and go, without pre-heating it (that 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 very difficult and tolerant motor-- it will not like it however you most likely will not eliminate it. Otherwise, it's not smart.

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

Blends with different solvents and/or with unleaded gasoline are "experimental at best", little or nothing is understood about their effects on the combustion qualities of the fuel or their long-term impacts on the engine.

Higher viscosity is not the only issue with using vegetable oil as fuel. Veg-oil has various chemical properties and combustion characteristics from the petroleum diesel fuel for which diesel motor and their fuel systems are created.

Diesel engines are modern devices with very exact fuel requirements, specifically the more modern, cleaner-burning diesels (see The TDI-SVO controversy).

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

Otherwise using veg-oil fuel needs either an expert SVO service or biodiesel. Mixes and blends are normally a bad compromise. But blends do have a benefit in winter.

As with biodiesel, some kerosene or winterised petro-diesel fuel blended with straight grease reduces the temperature level at which it begins to gel. (See Using biodiesel in winter season) More about fuel mixing and blends.