Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Diesel Trucks and Biodiesel

I’m in the market for a diesel truck, and would like to run it on my homebrewed diesel. I’m in CA and have been reading a lot of differing information. If we take the warranty out of the equation, is it OK to run a 2008 and newer diesel truck on a non-petroleum based biodiesel? What are the potential problems that could occur?

Most success running biodiesel that I am aware of is in situations of high consumption. I really don’t think it’s practical to use biodiesel unless the fuel turnover is high. Some vehicles that use biodiesel, start on regular fuel, run bio then run on regular before shut off and storage. I would not be in the market for a diesel truck And the expense involved unless I had talked to technicians for the truck maker and other owners who have experience using biodiesel.

Btw, why would you ever take the warrenty out of the equation. Even if the truck you buy is beyound it’s warrenty period, the allowances in that warrenty tell you valuable information for what may be acceptable in it’s operation.

Most modern diesels are limited to B5, maybe B10, the properties of B100 biodiesel don’t seem to be compatible with modern diesel engines. I wouldn’t do it.
Here’s a compatibility table:

And here’s an article:

Sounds like no modern (2008 and newer) road vehicles are compatible with more than B20, many specify max of B5.

And NOTE: the factory allowance for B5 or B20 is for commercially-available, carefully prepared B5 (or B20). I don’t know that your home brew would meet those specs.

There’s another problem with homemade diesel fuel. You have to pay taxes on it. This means that you have to maintain books that show how much you used. I would imagine if the tax police chose to check you out, you would have to show a ledger of how much you used and when you used it. This seems like a hassle to me. Of course, you don’s have to pay the taxes - until you get busted. Then I’m sure there are fines.

Here’s an example of how problematic using the wrong fuel with a modern diesel can be (VW TDI):

Actually you don’t have to pay federal taxes. The trick is all companies who sell gas/deisel operate across state lines. Thats commerce clause issues. If you produce and consume fuel privately without crossing state lines you may not owe any federal fuel tax.

What about state taxes?

Other states want a piece of the action too, no doubt.

I never mentioned state taxes specifically because each state does this differently. Most states actually bill the tax to the wholesaler. The retailers put the sign up as self defense or state law depending. If you are a self producer of fuel for your own consumption many states do not even have a law and procedure to collect the tax you may or not owe. The feds cannot tax purely in state self producers. As your link points out Maryland has a rule for this. But they also rely on the honor system. And they also are vague on the use of fuel on your own property. But farmers already get a tax break/refund for fuel used on the farm.

Today’s sophisticated light-duty diesel engines, computer controlled, emissions controlled, are not likely to tolerate a fuel for which they were not designed…The older, H.D. diesel engines ran 22 to 1 compression ratios and were much more tolerant of different fuels…Today’s 16.5 compression engines run quiet and smooth and squirt a little “Diesel Emissions Fluid” into the exhaust stream to make the EPA happy…You start burning home-made bio-diesel in one of those, might not turn out as planned…