G3408C and G3412C Engines Caterpillar

Lubrication System

Lubricant Recommendations

Due to significant variations in the quality and in the performance of commercially available oils, Caterpillar makes the following recommendations:

• Cat NGEO (Natural Gas Engine Oil)

• Cat NGEO EL350 ( Natural Gas Engine Oil)

The proper SAE viscosity grade of oil is determined by the minimum ambient temperature during cold engine start-up, and the maximum ambient temperature during engine operation. To determine the oil viscosity that is required for starting a cold soaked engine, refer to the minimum temperature in Table 1. To select the oil viscosity for operation at the highest anticipated ambient temperature, refer to the maximum temperature in the Table. Use the highest oil viscosity that is available in order to meet the required temperature during start-up.

For further information about oils, see Special Publication, SEBU6400, "Caterpillar Gas Engine Lubricant, Fuel, and Coolant Recommendations".

Lubricant Capacities

The capacity of the lubrication system includes the capacity of the oil filters that are installed at the factory.

Optional auxiliary filters require additional oil.

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Illustration 1	g00848238
Oil pan for G3400C Engines (1) Standard oil pan

Fuel

Fuel Recommendations

Caterpillar gas engines will operate successfully on a broad range of gaseous fuels. Pipeline natural gas has been used for many years. Commercial fuel gases are mixtures of gases. These fuels consist primarily of hydrocarbons (combinations of hydrogen and carbon) and some inert gases. The compositions of these gas mixtures have extreme variations. Fuels such as wellhead gas, bio-gas, and manufactured gas need to be reviewed for acceptability. Analyze the fuel in order to determine the following characteristics:

• Composition

• Contaminants

• Heat value

• Methane number

• Specific gravity

Field gas can have varying characteristics of combustion. Field gas can contain numerous harmful impurities. The impurities can alter the BTU content. The impurities can also alter the methane number. The impurities include everything from water up to complex hydrocarbons that can lead to detonation and severe engine damage. To minimize these effects, Caterpillar recommends the following guidelines:

1. Evaluate the fuel with the Caterpillar Methane Number Program, LEKQ6378.

   Methane values below 30 are not recommended for use in a Caterpillar engine. Fuels with a methane number that is below 30 must first be processed in order to remove harmful impurities in the fuel and raising the methane number into the acceptable range.

2. If necessary, use an engine that is configured for a fuel that has a high energy. Consult the appropriate manual for the engine in order to determine the recommended engine timing.

3. Reduce the oil change interval according to the results of the oil analysis.

For further information on fuels, see Special Publication, SEBU6400, "Caterpillar Gas Engine Lubricant, Fuel, and Coolant Recommendations".

Cooling System

Coolant Recommendations

During shipping and storage, the engine must be protected from damage that can be caused by freezing of the cooling system. If the engine is shipped to a site with freezing temperatures and/or if the engine is stored in a location with freezing temperatures, the cooling system must contain antifreeze that will withstand the lowest ambient temperature. Frequently check the concentration of glycol in the coolant/antifreeze. Make sure that the concentration is adequate in order to prevent freezing. Otherwise, the cooling system must be completely drained.

Coolant/antifreeze is normally composed of three elements: water, glycol and additives. Each element must meet specific guidelines.

Water

Deionized water or distilled water is recommended for use in engine cooling systems. If distilled water or deionized water is not available, use water with the properties that are listed in Table 4.

If you are not sure about the properties of your water, consult one of the following sources for a water analysis:

• Caterpillar dealer

• Local water utility company

• Agricultural agent

• Independent laboratory

Glycol

Preferred - Cat NGEC (Natural Gas Engine Coolant)

Alternatively, use Cat DEAC (Diesel Engine Antifreeze/Coolant) or a commercial heavy-duty coolant/antifreeze that meets "ASTM D6210" or "ASTM D4985" specifications.

Acceptable - In applications that do not require protection from boiling or from freezing, a mixture of Cat SCA and water that meets the properties that are listed in Table 4 is acceptable.

Note: The preferred coolant/antifreeze and the acceptable mixture of SCA and water require different concentrations of SCA. Refer to the Special Publication, SEBU6400, "Supplemental Coolant Additive (SCA)" topic.

Table 5 is a list of the coolant/antifreeze that is recommended for Caterpillar Gas Engines. The service life of the coolant/antifreeze that is used in Caterpillar Gas Engines is also listed. To achieve this service life, the coolants must be properly maintained. The maintenance program includes S·O·S coolant analysis.

Additives

Preferred - Cat Supplemental Coolant Additive (SCA)

Acceptable - A commercial SCA that provides 1200 mg/L (70 grains per US gal) or 1200 ppm of nitrites in the final mixture of coolant/antifreeze

Note: A 50/50 concentration of Cat NGEC or of Cat DEAC does not require a treatment with an SCA at the initial fill. Commercial heavy-duty coolant/antifreeze that meets "ASTM D6210" or "ASTM D4985" specifications may require a treatment with an SCA at the initial fill. Read the label or the instructions that are provided by the OEM of the product.

To ensure that the correct amount of SCA is in the cooling system, the concentration of SCA must be tested on a scheduled basis. Obtain an S·O·S coolant analysis (Level 1) or use a test kit to check the concentration of the SCA according to this Operation and Maintenance Manual, "Maintenance Interval Schedule".

For further information on coolant, see Special Publication, SEBU6400, "Caterpillar Gas Engine Lubricant, Fuel, and Coolant Recommendations".

Coolant Capacities

To properly maintain the cooling system, the Total Cooling System capacity must be determined. The Total Cooling System capacity will vary between individual installations. The External System capacity includes the following components: engine, expansion tank, heat exchanger, radiator and piping. Refer to the specifications that are provided by Caterpillar or by the OEM of the equipment. Record the Total Cooling System capacity in the appropriate Tables: