Diesel JD
Full Access Member
I think your used motor oil is probably changed before it gets bad enough to have a lot of corrosive stuff in it. Most people are driving gas motors and they aren't as ******* motor oil as diesels. My parents 4Runner still showed a good oil analysis from Blackstone when I changed it last time at 9500+ miles, so I'm going for 10,000+ this interval, just changed the filter at around 5500 miles and topped it off. I never let the oil stay in my diesel longer than 2500-3500 miles and it usually needs 1-2 quarts of make up oil, also not too nasty yet by the time it gets drained. I guess my biggest concern would be what might be on the bottom of somebody's used motor oil tank, stuff like water, antifreeze, chunks of junk. Filtering can eliminate most of that, perhaps not all. As far as homebrewing biodiesel, it may or may not be expensive, it IS time consuming, to varying degrees depending on how well you can automate your system and how good you get at it. The price usually depends on how cheap you can get methanol and wvo. Of course methanol is made from natural gas and it is a commodity and a "fossil fuel" so you're still subject to the intricacies of the world market. The NaOH or KOH is cheap relatively speaking. You could use ethanol or E85 as your alcohol but it gets harder to make acceptable biodiesel with that.