‘For the most part if it will burn it will run on it!’
Eight miles to the gallon sounds like a dealbreaker, and for most people, it would be. In this unique situation, the math actually works out.
This man is turning heads as he shows off how he runs a military surplus truck for free because of war-era engineering most people have never heard of. Would this make you want to drive one?
In a video posted by AJ (@the_offgridguru), he replied to a commenter who pointed out that his car’s fuel efficiency sucked. “The problem is that you get 8 miles to the gallon on a good day,” the commenter wrote.
AJ said it was a fair point but missing context.
The truck in question is an M35A2, a military cargo truck. The reason the fuel economy barely registers as a concern for AJ comes down to the engine.
“It is equipped with a Hercules multi-fuel engine,” he says.
AJ explains that when these trucks were originally built for the military, the whole point was that if supply chains got cut off or blockaded, soldiers still needed a way to keep vehicles moving. So, the engine was designed to run on pretty much anything combustible. AJ says he’s spoken with Vietnam veterans who drove these trucks and described improvising fuel in the field in ways that the average person would never think to try.
“They would go to those big transformer boxes—they were full of oil—they would put a bucket underneath of them, and then they would aim up and shoot the transformer, and it would drain mineral oil down into the bucket,” he says.
“Of course, it’s loaded with all kinds of chemicals that will definitely give you cancer, and they would use that for fuel,” he adds.
AJ shared that he runs his truck almost entirely on donated used motor oil, which would otherwise get thrown away after an oil change.
“I feed it predominantly used motor oil, and I get a lot of it donated,” he says. “Pulling a camper, it will only get like seven, eight miles to the gallon, but those gallons are essentially free to me, so it really doesn’t matter.”
“Fuel is not a problem when you are recycling waste motor oil. I can essentially drive my truck for free,” he says in the caption.
The concept of fueling a vehicle on waste oil isn’t new, but it’s also not as plug-and-play as AJ makes it look, at least for most diesel engines.
The core problem is viscosity and contamination, experts say. Used motor oil is thicker than diesel and full of random muck from engine wear. Without processing, it doesn’t burn cleanly and can seriously damage your engine.
Making it work requires processing the oil first. US Filtermaxx explains that the route involves settling the oil for weeks to let solids drop out, then running it through a centrifuge to pull out water and fine particles, then blending it with a solvent (usually diesel or gasoline) to thin it down. In warmer climates, the mix can be heavier, but in cold weather, more thinning is required, or the oil starts to coagulate.
The Drive profiled a YouTuber who converted his diesel Humvee to run on used vegetable oil collected from local fast food restaurants. The setup costs anywhere from $100 to $1,000, done properly, though he largely improvised his with dollar store supplies.
The truck fired right up and apparently smelled strongly of fast food, but the oil solidified in cold weather, leaving the Humvee stranded until temperatures warmed back up.
The comments section filled up fast with people who either wanted one immediately or already knew exactly what this engine could do.
“So for the most part if it will burn it will run on it! Lol kinda like the Chrysler Turbine car. Will be honest I have always wanted a deuce and a half, this makes me want one more!” a top comment read.
“I miss driving my M35a2 in the Army. WE ran diesel most of the time but I have also ran a mix of jp. Mogas and used oil,” a person said.
“Could you run it on used cooking oil? If so I’m gonna start car shopping,” another wrote.
Motor1 reached out to AJ for comment via Instagram and Facebook direct messages. We’ll be sure to update this if he responds.
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– The Motor1.com Team