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

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

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

3. Convert it to biodiesel.

The very first two methods sound simplest, but, as so typically in life, it's not quite that easy.

1. Mixing it

Grease is a lot more viscous (thicker) than either petro-diesel or biodiesel. The function of blending it or mixing it with other fuels is to decrease 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 (like # 1 diesel) you're still utilizing fossilfuel-- cleaner than many, however still not tidy enough, many would state. Still, for every 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 blends, varying from 10% grease and 90% petro-diesel to 90% vegetable oil and 10% petro-diesel. Some individuals just use it that method, begin up 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 very tough and tolerant motor-- it will not like it however you probably will not 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, ideally utilizing pure petro-diesel or biodiesel for starts and stops. (See next.) In which case there's no need for the blends.

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

Higher viscosity is not the only issue with utilizing grease as fuel. Veg-oil has different chemical homes and combustion qualities from the petroleum diesel fuel for which diesel engines and their fuel systems are designed.

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

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

Otherwise using veg-oil fuel needs either a professional SVO solution 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 blended with straight veggie oil lowers the temperature at which it starts to gel. (See Using biodiesel in winter season) More about fuel mixing and blends.