Seems like there is some interest in the real pros and cons, so let me try my best to explain all of them!
As far as pros, i can only think of a fuel. The biggest....free fuel. You cant top that one. I've also heard that it is better for your engine, and it actually cleans it as it burns, and adds extra lubrication. Again, this is what i have heard, i dont know if its true or not, so to me i dont look at it as a pro. its just a fact that might be true, might not be. not at all a deciding factor in my WVO decision.
There arent any more pros that i can think of. Maybe some people do it for the environment, i dont know....honestly, im not a big environmental guy....i just want my free fuel
Okay....cons. Theres alot of them. But to me personally none of them beat free fuel!
First off....its a dirty dirty process. You get old veggie oil all over you, your sticky, and it dries black, you ruin clothes, you ruin shoes. For me, a dickies jumpsuit is going to be a smart investment for our next tour.
Secondly, you dont always find it. Not all resturants have good oil, so some days you might be driving around searching for 3 hours or so. We are always on the go, and having to drive an average of about 400 miles a day and be at a show at a certain time, there comes a point when we have to stop searching and just buy diesel if we dont find it.
There are a few tests that you have to do in order to see if WVO is usable or not. There is good and bad WVO. some has water in it, some has animal fat in it. salt and sugar were originally thought to be not good, but turns out that they are not soluble in oil, so salt and sugar just passes through your system and doesnt do damage.
Once finding WVO we filter it. We have a pair of 2 micron filters that we use. The pump is half hour on, half hour off. With new filters, a half hour will pump about 60 gallons or so. Now how long the filters last, all depends on how good the oil you choose to filter is. That is why we spend alot of time looking for good oil. Theoretically you can filter most oil, but we have had our filters last for almost 1000 gallons of oil, and we have picked bad oil and killed our filters after almost 10 gallons.
Filters cost 15 bucks each. And is the only maintenance that we have to do. We also have a 10 micron filter that goes between the clean veggie and the fuel filter. This has to get changed every 3000 miles or so.
Even if you choose bad WVO and you have to change your filters every day....$30 is not a big deal compared to spending hundreds on fuel.
I have heard stories of people breaking down from WVO. We have yet to. We havent encountered any mechanical problems due to it. Seems like those that do, are those that dont really filter the WVO and just take 5 gallon buckets and dump it into the tank.....YES THERES PEOPLE THAT ACTUALLY DO THAT! not sure if they know, but water and food particles are probably not the best for their engines!
You just gotta ask yourself if it makes sense to go through all of that. For us, it is.
Here is a video tour blog that we did, and part of it shows us doing the WVO....for those curious on how the process of filtering works