There are at least 3 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 simply as it is-- usually 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 techniques sound easiest, but, as so frequently in life, it's not rather that basic.

1. Mixing it

Grease is far 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 mixing veg-oil with petroleum diesel or kerosene (very same as # 1 diesel) you're still utilizing fossilfuel-- cleaner than many, but still unclean enough, numerous would state. Still, for every single gallon of

grease you utilize, that's one gallon of fossil-fuel saved, which much less climate-changing carbon in the environment.

People utilize different mixes, varying from 10% vegetable oil and 90% petro-diesel to 90% grease and 10% petro-diesel. Some utilize it that way, launch and go, without pre-heating it (which makes veg-oil much thinner), or 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 tough and tolerant motor-- it won't like it however you most likely will not eliminate it. Otherwise, it's not wise.

To do it appropriately you'll require what amounts to an SVO system with fuel pre-heating anyhow, preferably 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 "experimental at finest", little or nothing is known about their impacts on the combustion qualities of the fuel or their long-term effects on the engine.

Higher viscosity is not the only problem with using veggie oil as fuel. Veg-oil has different chemical homes and combustion attributes from the petroleum diesel fuel for which diesel motor and their fuel systems are designed.

Diesel motor are modern devices with very precise fuel requirements, especially the more contemporary, cleaner-burning diesels (see The TDI-SVO controversy).

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

Otherwise utilizing veg-oil fuel requires either a professional SVO option or biodiesel. Mixes and blends are typically a poor compromise. But mixes do have a benefit in winter.

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