Biodiesel Myth #4 – Biodiesel Will Void My Warranty

In a multi-part series about biodiesel, this is one of several articles in an attempt to dispel the myths about biodiesel and it’s use in commercial and private diesel engines.

Myth #4 – Biodiesel Will Void My Warranty

In a word, No.   This is a myth perpetuated by people that either don’t understand the issue or are trying to keep the status quo. For engine manufacturers of engines and fuel injection equipment, the manufacturers warranty their products against defects of materials & workmanship, not the fuel.  No engine is warrantied against bad fuel, even if it’s petroleum fuel.

Magnuson-Moss Warranty Act

The Magnuson-Moss Act (P.L. 93-637) is a United States federal law (15 U.S.C. § 2301 et seq.). Enacted in 1975, it is the federal statute that governs warranties on consumer products.

Certain items specific to the Magnuson-Moss act apply to biodiesel which specifically exclude engine manufacturers, or car/truck dealers from requiring someone to use petroleum diesel (or even a specific blend of biodiesel) to fuel the car:

The Act provides that any warrantor warranting a consumer product to a consumer by means of a written warranty must disclose, fully and conspicuously, in simple and readily understood language, the terms and conditions of the warranty to the extent required by rules of the Federal Trade Commission. The FTC has enacted regulations governing the disclosure of written consumer product warranty terms and conditions on consumer products actually costing the consumer more than $15. The Rules can be found at 16 C.F.R. Part 700.

Under the terms of the Act, ambiguous statements in a warranty are construed against the drafter of the warranty.   Likewise, service contracts must fully, clearly, and conspicuously disclose their terms and conditions in simple and readily understood language.

Warrantors cannot require that only branded parts be used with the product in order to retain the warranty. This is commonly referred to as the “tie-in sales” provisions, and is frequently mentioned in the context of third-party computer parts, such as memory and hard drives.

Thus, you are free to use any fuel you wish, as long as it meets the qualifications as an approved motor fuel for use in the type engine (in this case combustion) you have purchased.  Since biodiesel purchased from a reputable, registered biodiesel supplier (like TBI) meets or exceeds the ASTM D6751 standard, the fuel can be used in any diesel engine without fear of voiding the warranty.

With biodiesel that meets the D-6751 specification, there have been over 45 million miles of successful, problem-free, real-world operation with B20 blends in a wide variety of engines, climates, and applications. The steps taken by the biodiesel industry to work with the engine companies and to ensure that fuel meets the newly accepted ASTM standards provides confidence to users and engine manufacturers that their biodiesel experiences will be positive and trouble-free.

For more information about biodiesel blends and engine warranties, see the NBB guidelines at:

Biodiesel Blends above 5% and engine warranties:

Biodiesel and OEM Warranties –