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

1. Use the oil simply 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 gas;

3. Convert it to biodiesel.

The first two methods sound easiest, however, as so often in life, it's not quite that basic.

1. Mixing it

Vegetable oil is much more thick (thicker) than either petro-diesel or biodiesel. The purpose of mixing 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 using fossilfuel-- cleaner than many, however still unclean enough, many would say. Still, for every gallon of

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

People utilize different blends, ranging from 10% vegetable oil and 90% petro-diesel to 90% grease and 10% petro-diesel. Some people simply use it that way, start up and go, without pre-heating it (that makes veg-oil much thinner), or perhaps utilize pure 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 most likely won't kill it. Otherwise, it's not sensible.

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 requirement for the mixes.

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

Higher viscosity is not the only problem with using grease as fuel. Veg-oil has different chemical residential or commercial properties and combustion characteristics from the petroleum diesel fuel for which diesel engines and their fuel systems are created.

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

They're hard however they'll only take a lot abuse. There's no guarantee of it, but utilizing a blend of as much as 20% veg-oil of great quality is said to be safe enough for older diesels, specifically in summertime.

Otherwise using veg-oil fuel requires either a professional SVO service or biodiesel. Mixes and blends are usually a bad compromise. But mixes do have an advantage in cold weather.

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