This is a bulletin from GM on fuel additives. Whatever you use, just be sure it doesn't have any emulsifiers in it, such as alcohol, which suspend water in the fuel and therefore bypass the operation of a typical water separator. GM finally released their own fuel conditioner, which I believe is made by Racor, but there are other brands which don't use emulsifiers. Standadyne and Racor are the only ones that I know of for sure, but others may be good too. As far as gelling, the fuel distributors already mix #1 and #2 diesel, regionally, to prevent this. So unless it gets way below 0 F, you shouldn't have a problem-at least I haven't. For the fungi growth, this is usually related to warmer weather and it requires some amount of water in the fuel for it to be active; so keep your tanks on the full side and get your fuel from high volume stations when possible to prevent this. Bottom line is, keep the water out and separate whatever may gets in there, and you shouldn't have any problems. Here is the bulletin.
Subject: Information on Diesel Fuel Additives #03-06-04-017B - (09/07/2005)
Models: 2006 and Prior Light Duty and Medium Duty Trucks
2006 and Prior Isuzu Commercial Medium Duty Models
2006 and Prior HUMMER H2
with 6.5L, 6.6L, 7.2L or 7.8L Diesel Engine (VINs F, P, S, Y, 1, 2, B,
3 --
RPOs L65, L49, L56, L57, LB7, LLY, LC8, LG4)
This bulletin is being revised to add model years, enhance the content and
add GM diesel fuel conditioner. Please discard Corporate Bulletin
Number 03-06-04-017A (Section 06 -- Engine/Propulsion System).
Important: The use of diesel fuel additives is not required or recommended
for the 6.5L diesel or the 6.6L Duramax® 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. GM Diesel Fuel Conditioner
®, P/N 88861009 (in Canada, 8886103
or both *Racor Power Shot Plus® and
*Stanadyne® 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.
Common Diesel Fuel Concerns
Fuel Waxing/Icing
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 diesel fuel biocides available that are designed to kill bacterial
growth in the fuel system. However, the dead bacteria can still cause
blockages throughout the fuel system. If bacterial growth is found in the
fuel system, the proper method of removal is to flush the fuel system using
Service Manual procedures, replace the fuel filter element and refill the
tank with clean diesel fuel. If a customer desires to use a biocide after
flushing the fuel system, it should not contain alcohol or other water
emulsifiers.
Low Cetane Number
The cetane number is one indicator of a diesel fuel's ability to ignite.
There are many indicators of overall fuel quality such as cleanliness,
specific gravity, volatility, viscosity, detergency, corrosion inhibiting
abilities, and lubricity. Increasing the cetane number alone is not a fix
for poor quality fuel. Additionally, increasing the cetane number beyond
the engine's requirements will not increase performance. However, the
cetane number of diesel fuel is not always consistent and some customers
may desire to use a cetane improver to ensure full performance of their
engine. If such an additive is to be used, it must not contain alcohol or
other water emulsifiers.
Poor Lubricity
The 6.5L diesel and the 6.6L Duramax® Diesel engines are designed to
operate on today's low sulfur fuel without the use of additives. A fuel
additive designed to increase lubricity is not a fix for poor quality or
contaminated fuel, but some customers may desire to use a lubricity
additive to aid in the longevity of their fuel system components. If such
an additive is to be used, it must not contain alcohol or other water
emulsifiers.
Fuel Source Issue
If a vehicle is properly maintained but has fuel contamination issues,
consider obtaining fuel from a different source. Purchasing fuel from a
high volume fuel retailer increases the chance that the fuel is fresh and
of good quality.
|---------------------------+---------------------------------------------|
| Part Number | Description |
|---------------------------+---------------------------------------------|
| 88861009 | Conditioner, Diesel Fuel 325 ml (11 oz) |
| | |
| | |
| (in Canada, 8886103
| |
|---------------------------+---------------------------------------------|
