What fuel additive, if any?

[Geo]

I am on my 2nd injection pump in 80k miles :( The service mgr at GMC said that a SB was out that said GM recommends that NO fuel additive be used!?? I give up... darned if you do and darned if you don't. Please give real world input on what is the best fuel additive - if any. Thanks! BTW I had been using Power Service regularly....

[steve-r]

I started adding Stanadyne Lubricity formula with my last new IP.
got a copy of this bulletin from AllData-

Diesel Engine - Fuel System Additive Recommendations

File In Section: 06 - Engine/Propulsion System

Bulletin No.: 03-06-04-017

Date: March, 2003

INFORMATION

Subject:
Information on Diesel Fuel Additives

Models:
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.

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 which 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 celane 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(R) 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 ISSUES

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.

[ 10-07-2003, 07:55 AM: Message edited by: steve-r ]

[lineman]

Geo,I only use Stanadyne performance additive.I belive this helped me to get 170000k out of my 93 mechancial injector pump before it went bad.I use it year round,and I get it at the Stanadyne dealer here in town.

[Shad]

I just bought 2 jugs of power-service all season conditioner treats 300 gal per bottle for 10.00 at wal-mart. I don't know if its as good as stanadyne or others, but should work.

[LanceW]

**post edited by author due to author having his headlight plugged into his taillight socket during the writing process**

[ 10-08-2003, 10:41 AM: Message edited by: LanceW ]

[jspringator]

LanceW, I am not sure Power Service is an emulisifer. I e-mailed Power Service with that question, and received a response which I posted on this board. My recollection is that Power Service is the right type for our engines. I can't find that e-mail, and of course all the old posts are gone.

[LanceW]

james- whoa, thank you, I stand corrected... just checked the Power Service site and they state "no alcohol"... my mistake. They are a demulsifier. I will double-check the jug at home but it looks like I am wrong. Got a little confused over which were good and which were bad too...

The only correct things in my earlier post were that GM recommends demulsifiers and there have been some highly spirited debates about which is really better. Power Service follows GM's recommendation, but some very knowledgeable members have pointed out that it could promote microbe growth and that if you are using a demulsifier then a biocide is also a good idea. As I proved in the above post, I am no expert but this is the type of additive that GM calls for.

sorry bout that, my bad. Where is George Morrison, he is the fuel expert and I believe he is in the "emulsifier" camp and does a very good job of explaining why...

[ 10-08-2003, 10:49 AM: Message edited by: LanceW ]