Top 5 Biodiesel-Ready Vehicles

One of my readers, Joseph, recently asked me a question about some previous articles I had written about biodiesel which you can see by clicking here.

Here's Joseph's question:

Dear John,

Amusing and informative articles. Thank you very much for taking up this biodiesel topic and de-mystifying it for those of us who are new to the bio diesel world.

I am looking at buying a cheap, older diesel truck for my company. I have been told that the engine must have direct injection in order to work with vegetable oils - at least, without modification. Is this true?

If so, do you happen to have a short list of vehicles which have direct injection engines, or a resource for such a list? I'm seeking something in the realm of a Ford F150 or F250, Chevy 1500, or possibly an Econoline type van.

I appreciate your guidance and thoughts. Thanks!

Joseph

Some Background on Direct Injection

Joseph, thanks for your note and this great question! Before I can give you with an answer, I think it's fair for the rest of the readers that I provide a little bit of background information.

Joseph made reference to the term direct injection, which is a specialized form of engine fuel delivery. Fuel injection atomizes the fuel by forcibly pumping it through a small nozzle under high pressure directly into a diesel engine's combustion chamber. The resultant atomization allows for better mixing of the fuel with the intake air. This in turn results in an overall thorough and efficient burn. This further results in overall greater efficiency and better fuel mileage (miles per gallon) than an engine using a carburetor or similar pre-engine aspiration method.

While diesel engines have never used carburetors (perhaps with exception to some very old models), many older gasoline engine cars and trucks used carburetors to mix fuel with air before allowing that charge of fuel-air mixture into the engine. This said, now you know what direct injection means.

Depending on which vehicle manufacturer you're talking about, direct injection may come in several forms. For example, older Volkswagen Vanagon (bus) vehicles had direct injection (DI) engines, later on the opportunity to augment DI engines with turbochargers showed up on the market. Nowadays, Volkswagen cars in several different models - such as The Jetta, Golf, and Beetle - now come in what's called TDI - short for turbocharged direct injection. Other automobiles, such as those trucks which support heavy-duty Cummins diesel engines, come stock with turbochargers to augment their already beefy power.

(Joseph, to answer your question, every diesel engine I know of has used direct injection. You mention modification: I will discuss this later.)

Some Words of Caution

Getting back to Joseph's original question, what are the cars and trucks are available which can readily burn biodiesel? Theoretically, all diesel engined vehicles can burn biodiesel.

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 butter - 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.

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.

Five Common "Diesel Ready" Cars and Trucks

With all of this background information provided, here is our short list of five common "biodiesel ready" vehicles:

• Ford F150, F250, and other similar diesel-engined trucks.
• Volkswagen Vanagon diesels - these are primarily the older models
• Volkwagen line of modern TDI vehicles, which include the Jetta/Bora sedans, station wagons, Golf, and Beetle.
• Mercedes Benz diesel models, both old and new.
• Ford "Econoline" cargo van diesel vehicles.

One of the more common follow-up questions that is asked of me with regard to biodiesel engines is the issue of so-called "conversion kits". My answer is simple: there are many shysters out there.

While I am not saying that these conversion kits don't work at all, I am saying that in many cases you don't even need to buy one. If you want to know more about this, then click here.

References / Other Reading:

John's Other Articles on Biodiesel