Which Diesel Cars & Trucks Can Use Biodiesel?

A Reader’s Question

A reader named Joseph recently asked me a question about “biodiesel ready” cars and trucks. Which vehicles can readily burn biodiesel? Theoretically, all diesel-engine vehicles can burn biodiesel.

History of Biodiesel Use

People have been using biodiesel in diesel engines ever since the diesel engine was patented by Rudolf Diesel back in 1898. A little known fact about diesel engines is that they were originally designed to use vegetable oil – namely peanut oil – as the primary fuel. However, soon after its invention and introduction into the mainstream engine market, use of petroleum based fuels was the norm, and therefore petrochemical diesel was used to power diesel engines afterwards. However, in recent decades a resurgence of using vegetable oil as the primary source of fuel has gained in momentum and popularity. While diesel engines were originally designed to burn 100% vegetable oil, no one can categorically say that all diesel engines can readily burn vegetable oil.

Experience Shows Most Cars Can Use Biodiesel

In my experience with the many people I have spoken with who have tried using 100% vegetable oil as biodiesel, each different model of car or truck has been able to successfully use vegetable oil biodiesel either as “straight” 100% vegetable oil, or some mix thereof. Based on this experience, any modern truck or car with a diesel engine under the hood could use vegetable oil as fuel. I make this statement with great caution for the simple reason that almost all car manufacturers do not make any claim to their vehicles’ ability to burn 100% vegetable oil.

Because the mainstream use of biodiesel with modern diesel engines is a relatively “new” notion, the use of biodiesel in a modern diesel engine is something to be done with caution. The reason for this is because modern diesel engines have been engineered precisely around the use of modern petrochemical diesel. What this means is that diesel engines are precisely tuned and honed to work specifically with a liquid fuel of precise given properties. If you are one to have experimented with biodiesel in its pure vegetable form, you might already know that vegetable oil is markedly thicker than stock diesel engine fuel.

There are other reasons that might suggest some incompatibility of using vegetable oil in a diesel engine. Some older diesel engines came stock with rubber O-rings, fuel hoses, and other older rubber-based components which were known to break down when exposed to vegetable oil based biodiesel fuels. The fix for this problem seemed relatively simple: replace all of the old rubber components with “modern rubber” such as nitrile.

A Word of Caution

Because diesel engine cars and trucks were designed with petroleum-based diesel fuel in mind, any modification to your engine system to use a different fuel (such as biodiesel) – and/or the actual use of this different fuel – is all done at your own risk. While in my experience, I have never heard of biodiesel damaging someone’s diesel engine,this is not to say it wouldn’t damage someone’s engine at some point in time.

References / Other Reading:

John’s Other Articles on Biodiesel
John’s Other Articles

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