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 secondhand oils.

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

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

3. Convert it to biodiesel.

The first two methods sound most convenient, 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 function of blending it or blending it with other fuels is to reduce the viscosity to make it thinner so that it flows 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 using fossilfuel-- cleaner than many, but still not clean enough, many would state. Still, for every single gallon of

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

People utilize different mixes, ranging from 10% grease and 90% petro-diesel to 90% veggie oil and 10% petro-diesel. Some individuals simply use it that method, begin up and go, without pre-heating it (that makes veg-oil much thinner), and even use 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 difficult and tolerant motor-- it won't like it however you probably will not eliminate it. Otherwise, it's not sensible.

To do it appropriately you'll require what totals up to an SVO system with fuel pre-heating anyway, preferably using pure petro-diesel or biodiesel for starts and stops. (See next.) In which case there's no need for the mixes.

Blends with various solvents and/or with unleaded fuel are "speculative at best", 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 issue with using grease as fuel. Veg-oil has different chemical homes and combustion attributes from the petroleum diesel fuel for which diesel engines and their fuel systems are developed.

Diesel engines are modern machines with extremely accurate fuel requirements, particularly the more modern-day, cleaner-burning diesels (see The TDI-SVO controversy).

They're tough however they'll just take a lot abuse. There's no warranty of it, however utilizing a blend of approximately 20% veg-oil of great quality is stated to be safe enough for older diesels, particularly in summertime.

Otherwise using veg-oil fuel requires either an expert SVO option or biodiesel. Mixes and blends are normally a bad compromise. But mixes do have a benefit 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 begins to gel. (See Using biodiesel in winter) More about fuel mixing and blends.