DIESEL FUEL CONTAMINATION FUEL ADDITIVE INFORMATION

SUBJECT: DIESEL FUEL SYSTEM CONTAMINATION 5.7L V-8 DIESEL ENGINES

Several forms of fungi and other microorganisms can survive and multiply in diesel fuel. The microscopic growths can occur in all areas of the fuel handling system -- storage tanks, pump trucks, delivery lines, and fuel tanks. These fungi grow into long strings and form large mats of globules. The growth appears slimy and usually is black, green or brown, although it may be any color. It may grow throughout the f uel or at the interface area between the fuel and water bottom layer. As the fuel is agitated, for instance during filling of the retail outlet storage tanks, fungal growth is distributed throughout the fuel system and, if a passenger car is fueled at that time, its fuel tank could receive contaminated fuel.

Fungi need only trace amounts of minerals and water to sustain their growth and use the fuel as their main energy source. As they grow and multiply, they chemically alter the fuel to produce water, sludge, acids, and other products of metabolism. Where they cling, they hold water and waste products against metal and other surfaces, thereby leading to corrosion. The most common condition is fuel filter plugging; however, the various metal components of the fuel system including the fuel tank and the injection pump can corrode.

Several companies market products which are claimed to control microbial growth in diesel fuel. One such product which Oldsmobile has found to be effective is BIODOR, marketed by U.S. Borax and Chemical Corporation. It is available in a form suitable for use in treating an automotive fuel system under the trade name BIODOR Diesel Doctor.

In those areas of the country where microbial contamination exists because of careless fuel handling, it is recommended that microbial contamination be controlled by use of the above product or its equivalent. Do not exceed the dosage recommended on the label. The dosage recommended is sufficient. Whenever continuously towing a trailer, discontinue the use of BDODOR Diesel Doctor. Resume dosage when trailer towing has ended. Cadillac uses BIODOR in the factory fill so that treatment of that fuel is not necessary.

It is recommended that you take advantage of the introduction of this product to remind your customers of the potential for microbial contamination of diesel fuels. Treatment of diesel fuel to prevent this condition is preferable to correcting the damage once it occurs. If microbial contamination is identified in a fuel system, the fuel tank should be cleaned reasonably well. Steam cleaning may be necessary only if you are unable to remove most of the microbial growth. The previously mentioned product or its equivalent will kill the growth, and in extremely contaminated tanks, the residue could float free and plug the filter if the excess debris is not removed.

Care should be exercised when working with those microorganisms to keep them out of open sores on the skin.

One source for BIODOR Diesel Doctor, is KREX, Inc. For convenience, a copy of their order form is attached.

This information, while obtained from sources believed to be reliable, is being forwarded as a matter of information only. There may be additional manufacturers of such products. Cadillac does not endorse, indicate any preference for, or assume any responsibility with respect to the products, equipment, or services mentioned therein or for any other such item which may be available from other sources.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.