Heating the WVO is not a must. The vehicle will operate with out the heating. However, this may put a huge strain on your system, cause early wear, or damage.

In this case, there are a couple of factors to take into account. Oil Viscosity and the quality of the Oil.

Oil Viscosity IS a factor in engine degredation. That is why most will agree that heating the oil is necessary in the vast majority of situations. To make the oil flow (etc.) better and act more like diesel. There are very few locations in the US where it is up around 120deg on a regular basis. So I would say heating is a necessity for SVO/WVO. How much heating would depend on your location, etc.

The other factor is Oil quality. It needs to be good quality oil. The dryer the better (NO suspended water). Water will tear up an injection pump really fast. You also need to filter the oil as much as possible. There are almost as many different filter setups as there are people doing the filtering.

Here is a link to a forum that has more extensive information . . .

biodiesel.infopop.cc General SVO Discussion

Good Luck!