There are at least three methods to run a diesel motor on biofuel using veggie oils, animal fats or both. All 3 are utilized with both fresh and pre-owned 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 blend it with a solvent, or with gas;

3. Convert it to biodiesel.

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

1. Mixing it

Grease is far more viscous (thicker) than either petro-diesel or biodiesel. The purpose of mixing it or blending it with other fuels is to decrease 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 (exact same as # 1 diesel) you're still utilizing fossilfuel-- cleaner than many, but still unclean enough, many would say. Still, for every gallon of

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

People utilize numerous mixes, varying from 10% grease and 90% petro-diesel to 90% vegetable oil and 10% petro-diesel. Some people just utilize it that method, launch and go, without pre-heating it (that makes veg-oil much thinner), or perhaps utilize pure veggie oil 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 an extremely difficult and tolerant motor-- it won't like it however you most likely will not eliminate it. Otherwise, it's not wise.

To do it effectively you'll require what amounts 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 mixes.

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

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

Diesel motor are modern machines with very exact fuel requirements, especially the more modern-day, cleaner-burning diesels (see The TDI-SVO debate).

They are difficult but they'll just take so much abuse. There's no assurance of it, but utilizing a mix of as much as 20% veg-oil of great quality is said to be safe enough for older diesels, specifically in summertime.

Otherwise utilizing veg-oil fuel requires either a professional SVO service or biodiesel. Mixes and blends are generally a poor compromise. But blends do have a benefit in cold weather.

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