Using biodiesel in your car

Biodiesel fuel that has been produced by a reputable manufacturer can be used in any diesel engine vehicle, including passenger cars, heavy-duty trucks, and farm equipment, without making any modifications to the engine. One of the most challenging issues with biodiesel as a fuel source is the quality of the fuel itself. While fuel standards for biodiesel have now been created, they are not nearly as stringent as those the United States has for gasoline and even for petroleum diesel. The lack of consistent quality among all producers is an issue that has everyone--the biodiesel industry, automakers, engine suppliers, and consumers--concerned.

Clogging is a greater issue with older diesel vehicles.

Because biodiesel fuel is made with vegetable-based products, the temperature it is stored at is more critical than with petroleum diesel. As a result, fueling stations need to treat biodiesel a bit differently than other fuels. If it sits in a warm storage tank for too long, it can grow mold, and if it is stored at too cold a temperature, it will thicken and become difficult to dispense. These problems typically occur if the biodiesel is not used quickly enough, so fuel stations can significantly reduce these issues by buying only enough biodiesel as their market demands.

Owners should also watch for signs that fuel filters and systems are clogging, particularly when biodiesel is first used. Biodiesel acts as a lubricant, which means that it can loosen deposits that are stuck in fuel lines and in the fuel tank, which in turn could clog fuel filters, injectors, or other parts of the fuel system.

Experts indicate that clogging is a greater issue with older diesel vehicles because higher mileage generally means greater deposits and with the newest technology for fuel injection, such as Mercedes-Benz's new compressed direct-injection diesel engines, where the pressure of the fuel being forced through the injectors is much greater than in the older-style diesel engines.

Since these issues relate only to pure biodiesel fuel, not blends, the risks of using biodiesel are significantly less, some even say insignificant, with low biodiesel blends. Today, most passenger vehicles will remain covered by the manufacturer's warranty if an owner is using B5 biodiesel. As production standards increase, manufacturers may warranty vehicles that use up to B20 biodiesel.

Where opinions deviate greatly is with biodiesel blends that use more than than 20 percent or with pure biodiesel. Many feel that even B100 that has been produced by a reputable manufacturer should not be used in a vehicle engine and could likely result in engine damage. Others feel that it may be possible to use B100 without any adverse effects so long as the quality standards are high.

Manufacturers may warranty vehicles that use up to B20 biodiesel.

There does, however, seem to be a consensus that purchasing used restaurant cooking oil locally and either making your own biodiesel at home or via an aftermarket system that is installed in your vehicle is not a good idea. One of the primary reasons is that biodiesel in general does not perform as well as petroleum diesel in cold weather, and biodiesel made from used cooking oil is even more significantly affected by cold weather than that made from soybeans. In simple terms, cold temperatures cause biodiesel to turn to a gel-like substance, which in turn cause clogs in fuel filters and lines. Despite the fact that there are a number of companies selling these aftermarket systems and instructions on how to make your own biodiesel at home are prevalent on the Internet, experts all agreed that these homegrown systems are likely to cause more harm than good.

More resources