Fuel

DIESEL ENGINE FUEL

NOTICE: Diesel fuel or fuel additives not recommended could damage your fuel system, fuel-operated heater (FOH) and engine. Your warranty would not cover this damage. And:
- Diesel fuel that has been mixed with engine oil or automatic transmission fluid could damage your engine and emission controls.
- Aftermarket diesel fuel additives are not tested by General Motors. Some additives, particularly those which contain alcohol or water emulsifiers, may damage your fuel system. If you believe that unique circumstances call for a fuel additive to be used, consult your dealer for advice.
- If you ever run out of diesel fuel, it can be difficult to restart your engine. To avoid this, never let your tank get empty.

If gasoline is ever accidentally added to the fuel tank, to avoid severe engine damage, do not run the engine until the fuel tank can be drained.

WHAT FUEL TO USE
In the United States, for best results use No. 2-D diesel fuel year-round (above and below freezing conditions) as oil companies blend No. 2-D fuel to address climate differences. No. 1-D diesel fuel may be used in very cold temperatures (when it stays below 0°F or -18°C); however, it will produce a power and fuel economy loss. Avoid the use of No. 1-D diesel fuel in warm or hot climates. It may result in stalling, poor starting when the engine is hot, and may damage the fuel injection system.

It is important that diesel-powered trucks are refueled only with ultra low-sulfur fuel. The emission control system requires the use of diesel fuel with ultra low-sulfur (0.0015% by weight, or 15 ppm, maximum) content. Both ultra low-sulfur and higher sulfur diesel fuels are available in the United States and ultra low-sulfur diesel fuel is available in Canada. However, only higher sulfur diesel fuel is available in Mexico. Use of fuels with higher-sulfur content will affect the function of the emission components and may cause reduced performance, excessive smoke, and unpleasant odor.

At a minimum, the diesel fuel you use should meet the latest version of ASTM specification D 975 (Grades No. 2-D or No. 1-D S15 commonly known as Ultra Low Sulfur diesel) in the United States. In addition, the Engine Manufacturers Association (EMA) has identified properties of an improved diesel fuel for better engine performance and durability. Diesel fuels corresponding to the EMA Recommended Guideline on Premium Diesel Fuel (FQP-1A) could provide better starting, less noise, and better vehicle performance. If there are questions about the fuel you are using, contact your fuel supplier.

It is acceptable to use diesel fuel containing up to 5% biodiesel (B5), but the final blended fuel must meet the same specification, ASTM D 975 (Grades No. 2-D or No. 1-D S15 commonly known as Ultra Low Sulfur diesel), as other fuels used in your vehicle, and the biodiesel used for making this fuel must meet the latest version of ASTM specification D 6751. Biodiesel is produced from vegetable oils or animal fat that have been chemically modified to reduce the possibility of damage to your fuel system and engine. Higher concentration (i.e., greater than B5) biodiesel-containing fuels or the use of unmodified bio-oils blended into diesel fuel at any concentration is not recommended and could damage your fuel system and engine. Such damage would not be covered by your warranty. If there are questions about the biodiesel-containing fuels you are using, contact your fuel supplier.

Diesel fuel may foam when you fill your tank. This can cause the automatic pump nozzle to shut off, even though your tank is not full. If this happens, just wait for the foaming to stop and then continue to fill your tank.

CAUTION: Heat coming from the engine may cause the fuel to expand and force the fuel out of your tank. If something ignites the fuel, a fire could start and people could be burned. To help avoid this, fill your fuel tank only until the automatic nozzle shuts off. Do not try to top it off.

WHAT FUEL TO USE: VEHICLES WITH SEO 5F4 ONLY (Bio-Diesel)

Notice: Any damage caused by the biodiesel fuel that does not meet these specification are not covered by your warranty.

For fleets requiring compliance to Executive order 13149 (EPACT credit mandate), a minimum B20 biodiesel blend is needed to qualify. For these users only, it is acceptable to use diesel fuel containing up to 20% biodiesel (B20). Do not use biodiesel blends in excess of 20% (B20). Higher concentration (i.e., greater than 20%) biodiesel-containing fuels or other unmodified bio-oils blended into diesel fuel at any concentration must not be used. The biodiesel portion used to make the B20 blend must meet the latest version of ASTM D 6751, Standard Specification for Biodiesel Fuel (B100) Blend Stock for Distillate Fuels, and the diesel fuel portion must meet the latest version of ASTM D 975 (Grade No. 2-D or 1-D S15) known as Ultra Low Sulfur Diesel, which are Standard Specifications for Diesel Fuel Oils.

Notice: Raw or refined vegetable oil, or recycled greases that have not been processed into biodiesel, are not biodiesel and should not be used. The use of unprocessed oil and greases blended into diesel fuel or degraded (aged) biodiesel could damage your fuel system and engine. Such damage would not be covered by your warranty.

If there are questions about the biodiesel-containing fuels you are using, contact your fuel supplier.

Some points you should be aware of when using up to B20 blends are:
- Biodiesel has less energy content than standard diesel fuel. If you are using B20, power, torque and fuel economy should be between 1% and 2% lower compared to standard diesel fuel. As the percent biodiesel in the blend is lowered, any differences in energy content become diminished.
- Biodiesel has a cleaning effect on accumulated sediments in tanks, and filter plugging may be experienced during the use of B20.
- Biodiesel has a greater tendency to oxidize than the standard diesel fuel, and thus, has a shorter storage life than standard diesel fuel. Frequent turnover of fuel in the tank is recommended to minimize problems.
- Biodiesel reduces the surface tension of the blended fuel, which results in the water separator coalescing element in your vehicle's fuel filter to be ineffective. Any water in the fuel will pass through the filter and may cause corrosion damage to the fuel system.

The BQ-9000 quality management system has been established by the biodiesel industry to ensure product quality. GM recommends that fleet owners purchase B20 from a Certified Marketer or from a marketer who offers fuel from an Accredited Producer under the BQ-9000 program.

WHAT FUEL TO USE IN CANADA
Canadian fuels are blended for seasonal changes. Diesel Type "A" fuel is blended for better cold weather starting (below 0°F or -18°C); however, you may notice some power and fuel economy loss. If Type "A" fuel is used in warmer temperatures, stalling and hard starting may occur. Diesel Type "B" fuel is blended for temperatures above 0°F (-18°C).

It is important that diesel-powered trucks are refueled only with ultra low-sulfur fuel. The emission control system requires the use of diesel fuel with ultra low-sulfur (0.0015% by weight, or 15 ppm, maximum) content. Both ultra low-sulfur and higher sulfur diesel fuels are available in the United States. Use of fuels with higher-sulfur content will affect the function of the emission components and may cause reduced performance, excessive smoke, and unpleasant odor.

At a minimum, the diesel fuel you use should meet the latest version of specification CAN/CGSB-3.517 (Low Sulfur Diesel) in Canada. In addition, the Engine Manufacturers Association (EMA) has identified properties of an improved diesel fuel for better engine performance and durability (FQP-1A). Diesel fuels corresponding to the EMA description could provide better starting, less noise, and better vehicle performance. If there are questions about the fuel you are using, contact your fuel supplier.

It is acceptable to use diesel fuel containing up to 5% biodiesel (B5), but the final blended fuel must meet the same specification, CAN/CGSB-3.517 (Low Sulfur Diesel) in Canada, as other fuels used in your vehicle, and the biodiesel used for making this fuel must meet the latest version of ASTM specification D 6751. Biodiesel is produced from vegetable oils or animal fat that have been chemically modified to reduce the possibility of damage to your fuel system and engine. Higher concentration (i.e., greater than B5) biodiesel-containing fuels or the use of unmodified bio-oils blended into diesel fuel at any concentration is not recommended and could damage your fuel system and engine. Such damage would not be covered by your warranty. If there are questions about the biodiesel-containing fuels you are using, contact your fuel supplier.

VERY COLD WEATHER OPERATION
Follow the instructions listed previously under the heading "What Fuel to Use."

NOTICE: Never use home heating oil or gasoline in your diesel engine. They can cause engine damage.

In cold weather, your fuel filter may become clogged (waxed). To unclog it, move the vehicle to a warm garage area and warm the filter to between 32°F and 50°F (0°C to 10°C). You will not need to replace it.

WATER IN FUEL

CAUTION: Diesel fuel containing water is still flammable. You could be burned. If you ever try to drain water from your fuel, keep sparks, flames and smoking materials away from the mixture.

NOTICE: If there is water in your diesel fuel and the weather is warm or humid, fungus and bacteria can grow in the fuel. They can damage your fuel system and fuel operated heater (FOH) (if equipped). A diesel fuel biocide can be used to sterilize your fuel system. However, your fuel system may still need to be cleaned. Your fuel tank may need to be purged to remove water. Improper purging can damage your fuel system and block your FOH.

Sometimes, water can be pumped into your fuel tank along with your diesel fuel. This can happen if a service station doesn't regularly inspect and clean its fuel tanks, or if it gets contaminated fuel from its suppliers.

IMPORTANT: The water must be drained from both chassis mounted fuel filters.