There are at least three ways to run a diesel engine on biofuel utilizing vegetable oils, animal fats or both. All three are used with both fresh and pre-owned oils.

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

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 approaches sound easiest, however, as so often in life, it's not rather that basic.

1. Mixing it

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

If you're mixing veg-oil with petroleum diesel or kerosene (same as # 1 diesel) you're still utilizing fossilfuel-- cleaner than the majority of, but still not clean enough, lots of would say. Still, for every gallon of

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

People utilize various mixes, ranging from 10% grease and 90% petro-diesel to 90% vegetable oil and 10% petro-diesel. Some people simply use it that way, launch and go, without pre-heating it (which makes much thinner), or perhaps use pure grease without pre-heating it, which would make it much thinner.

You may 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 won't 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 anyhow, ideally using pure petro-diesel or biodiesel for starts and stops. (See next.) In which case there's no need for the blends.

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

Higher viscosity is not the only issue with using grease as fuel. Veg-oil has various chemical residential or commercial properties and combustion qualities from the petroleum diesel fuel for which diesel motor and their fuel systems are developed.

Diesel engines are state-of-the-art makers with really precise fuel requirements, specifically the more modern, cleaner-burning diesels (see The TDI-SVO debate).

They are difficult but they'll just take so much abuse. There's no warranty of it, but utilizing a mix of approximately 20% veg-oil of good quality is stated to be safe enough for older diesels, especially in summer.

Otherwise using veg-oil fuel needs either a professional SVO solution or biodiesel. Mixes and blends are normally a poor compromise. But blends do have a benefit in winter.

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