Diesel Place banner
1 - 1 of 1 Posts

· Registered
9,792 Posts
Discussion Starter · #1 ·
File In Section: 06 - Engine/Propulsion System

Bulletin No.: 03-06-04-017

Date: March, 2003

Information on Diesel Fuel Additives

1994-1996 Chevrolet Chevy G-Van, Sport Van
1994-1999 Chevrolet Suburban, Tahoe, P Chassis
1994-2000 Chevrolet C/K 1500, 2500 Models
1994-2002 Chevrolet C/K 3500 Model
1996-2002 Chevrolet Express
2001-2003 Chevrolet Silverado
1997-2003 Chevrolet F Model (T Series) Medium Duty Tilt Cab
1999-2003 Chevrolet W Series Medium Duty Tilt Cab
2000-2003 Chevrolet WT5500 Model Medium Duty Tilt Cab
2003 Chevrolet 4500, 5500 Series Medium Duty Trucks
1994-1996 GMC G-Van (Rally Wagon, Vandura)
1994-1997 GMC Yukon
1994-1999 GMC Suburban, P Chassis
1994-2000 GMC C/K 1500, 2500 Models
1994-2002 GMC C/K 3500 Model
1996-2002 GMC Savana
2001-2003 GMC Sierra
1997-2003 GMC F Model (T Series) Medium Duty Tilt Cab
1999-2003 GMC W Series Medium Duty Tilt Cab
2000-2003 GMC WT5500 Model Medium Duty Tilt Cab
2003 GMC 4500, 5500 Series Medium Duty Trucks
1997-2003 Isuzu FSR, FTR, FVR Model Medium Duty Tilt Cabs
1999-2003 Isuzu NPR, NQR Model Medium Duty Tilt Cabs
2000-2003 Isuzu FRR Model Medium Duty Tilt Cab
with 6.5L, 6.6L, 7.2L or 7.8L Diesel Engine (VINs F, P, S, Y, 1, B, 3 - RPOs L65, L49, L56, L57, LB7, LC8, LG4)

The use of diesel fuel additives is not required or recommended for the 6.5L diesel or the 6.6L Duramax(R) Diesel engine under normal conditions. The filtering system is designed to block water and contaminants without the use of additives. However, some customers may desire to use fuel additives to improve the characteristics of available diesel fuels.

Water Emulsifiers and Demulsifiers

If the customer desires to use a fuel additive, care must be taken in its selection. There are two common methods that fuel additives use to cope with water in the fuel. One method is through demulsification of water in the fuel. This method causes water particles to combine together to form larger particles, which drop out of suspension. This allows the fuel filter/water separator to separate the water from the fuel as it is designed to. The other method of coping with water in the fuel is through emulsification. This method, often using alcohol as the emulsifier, keeps water particles suspended in the fuel. Emulsification of water in the fuel can allow water to get past the fuel filter/water separator, in most cases causing damage to the fuel system.

Only alcohol free water demulsifiers should be used in General Motors diesel engines. Both *Racor(R) and *Stanadyne(R) diesel fuel additives are alcohol free and utilize water demulsifiers to cope with water in the fuel. Other brands may be available in different areas; be sure that they clearly state that they are alcohol free demulsifiers before use.

*We believe these sources and their products to be reliable. General Motors does not endorse, indicate any preference for or assume any responsibility for the products from these firms or for any such items which may be available from other sources.


Fuel distributors blend # 1 and # 2 diesel fuels for seasonal requirements in a particular region. No other blending of fuels is recommended. However, a customer may desire to use a winter fuel additive to prevent fuel waxing or icing during extreme cold snaps. If a winter fuel additive is to be used, it should not contain alcohol or other water emulsifiers that may compromise the water removal effectiveness of the fuel filtering system.

Bacteria and Fungi Growth

Bacteria and fungi growth can occur in diesel fuel when there is water present, especially during warmer weather. The best prevention against bacteria and fungi growth is to use clean fuel that is free of water. There are diese
1 - 1 of 1 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.