There are at least 3 methods to run a diesel motor on biofuel utilizing veggie oils, animal fats or both. All three are used with both fresh and pre-owned oils.

1. Use the oil simply as it is-- typically 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 two methods sound simplest, however, as so typically in life, it's not quite that simple.

1. Mixing it

Grease is a lot more thick (thicker) than either petro-diesel or biodiesel. The purpose of mixing it or mixing it with other fuels is to lower the viscosity to make it thinner so that it flows more easily through the fuel system into the combustion chamber.

If you're mixing veg-oil with petroleum diesel or kerosene (exact same as # 1 diesel) you're still using 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 use numerous mixes, varying from 10% grease and 90% petro-diesel to 90% grease and 10% petro-diesel. Some people simply use it that way, launch and go, without pre-heating it (that makes veg-oil much thinner), and even utilize 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 most likely won't kill it. Otherwise, it's not smart.

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

Blends with numerous solvents and/or with unleaded gasoline are "speculative at finest", little or nothing is understood about their effects on the combustion characteristics of the fuel or their long-lasting results on the engine.

Higher viscosity is not the only issue with using grease as fuel. Veg-oil has various chemical 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 extremely accurate fuel requirements, specifically the more contemporary, cleaner-burning diesels (see The TDI-SVO debate).

They are difficult however they'll only take so much abuse. There's no warranty of it, however using a blend of approximately 20% veg-oil of good quality is said to be safe enough for older diesels, particularly in summertime.

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

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