Due to the significant variations in the quality and in the performance of commercially available oils, Caterpillar makes the following recommendations. The following recommendations are in order of oil performance:
- Cat Natural Gas Engine Oil (NGEO) EL350
- Cat Natural Gas Engine Oil (NGEO) EL250
- Cat Natural Gas Engine Oil (NGEO)
Cat natural gas engine oils are the preferred oils for use in ALL Cat natural gas fueled engines that are covered by Special Publication, SEBU6400. Commercial alternative natural gas engine oils are, as a group, second choice oils.
The proper SAE viscosity grade of oil is determined by the minimum ambient temperature during cold engine start-up. The proper SAE viscosity grade of oil is also determined by 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 to meet the required temperature during start-up.
| Cat NGEO SAE 40 Viscosity Grade Properties | ||||
|---|---|---|---|---|
| Characteristic | ASTM Test | Cat NGEO | Cat EL250 | Cat EL350 |
| API Gravity at |
"D0287" | 28 | 27.5 | 29.3 |
| Flash Point |
"D0092" | 252 | 262 | 247 |
| Pour Point |
"D0097" | −15 | −12 | −21 |
| Viscosity at |
"D0445" | 13.2 | 13.5 | 13.5 |
| Viscosity Index | "D2270" | 98 | 99 | 97 |
| Weight (Percent) of Sulfated Ash | "D0874" | 0.52 | 0.57 | 0.54 |
| Total Base Number | "D2896" | 5.6 | 6.5 | 6.2 |
For additional information about oils for gas engines, see Special Publication, SEBU6400, "Caterpillar Gas Engine Lubricant, Fuel, and Coolant Recommendations".
Caterpillar recommends the S·O·S oil analysis program to monitor the condition of the oil. The analysis can help determine the maintenance requirements for the engine. The S·O·S program is part of the preventive maintenance program. For further information about the S·O·S program, see this Special Publication, "S·O·S Services Oil Analysis" topic.
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 to prevent freezing. Otherwise, drain the cooling system.
Coolant/antifreeze is normally composed of three elements: water, glycol, and additives. Each element must meet specific guidelines.
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 2.
| Caterpillar Minimum Acceptable Water Requirements | ||||
|---|---|---|---|---|
| Property | Maximum Limit | ASTM Test | ||
| Chloride | |
"D512", "D4327" | ||
| Sulfate (SO4) | |
"D516" | ||
| Total Hardness | |
"D1126" | ||
| Total Solids | |
"D1888" | ||
| Acidity | pH of 5.5 to 9.0 | "D1293" | ||
| NOTICE |
|---|
|
Use of water that does not meet the recommendations for the cooling system will damage the cooling system. Do not use these types of water in the cooling system: sea water, softened water that has been conditioned with salt, hard water and tap water. Only use water that meets the recommendations for the cooling system. |
If you are not sure about the properties of your water, consult one of the following sources for a water analysis:
- Cat dealer
- Local water utility company
- Agricultural agent
- Independent laboratory
| NOTICE |
|---|
|
Do not use Extended Life Coolant (ELC) with Cat Gas Engines. ELC was not formulated for use in Cat Gas Engines. Do not use heat transfer fluids in Cat Gas Engines. Use only the coolant/antifreeze that is recommended. |
Preferred - Cat Natural Gas Engine Coolant (NGEC)
Alternatively, use Cat Diesel Engine Antifreeze/Coolant (DEAC) or a commercial heavy-duty coolant/antifreeze that meets "ASTM D6210" or "ASTM D4985" specifications.
| NOTICE |
|---|
|
Do not use a commercial coolant/antifreeze that only meets the ASTM "D3306" or equivalent specification. This type of coolant/antifreeze is made for light duty automotive applications. Use only the coolant/antifreeze that is recommended. |
Acceptable - In applications that do not require protection from boiling or freezing, a mixture of Cat SCA and water that meets the properties that are listed in Table 2 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 3 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 Cat 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.
| Recommended Coolant/Antifreeze and Service Life of the Coolant/Antifreeze | |
| Coolant/Antifreeze | Service Life (1) |
| Caterpillar NGEC | Three Years |
| Caterpillar DEAC | |
| Commercial Heavy-Duty Coolant/Antifreeze that meets "ASTM D6210" | Two Years |
| Commercial Heavy-Duty Coolant/Antifreeze that meets "ASTM D4985" | One Year |
| Caterpillar SCA and Water | Two Years |
| Commercial SCA and Water | One Year |
| (1) | The service life of coolant is also limited by use (service hours). Refer to the specific engine Operation and Maintenance Manual, "Maintenance Interval Schedule". |
Preferred - Cat Supplemental Coolant Additive (SCA)
Acceptable - A commercial SCA that provides
Note: A 50/50 concentration of Caterpillar NGEC or of Caterpillar 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, "Cat Gas Engine Lubricant, Fuel, and Coolant Recommendations".
Cat 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 must be reviewed for acceptability. Analyze the fuel 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:
- Evaluate the fuel with the Caterpillar Methane Number Program, LEKQ6378.
Methane values below 30 are not recommended for use in a Cat engine. Fuels with a methane number below 30 must first be processed to remove harmful impurities in the fuel. This process will also raise the methane number into the acceptable range.
- If necessary, use an engine that is configured for a fuel that has a high energy. Consult the appropriate manual for the engine to determine the recommended engine timing.
- Reduce the oil change interval according to the results of the oil analysis.
For further information on fuels, see Special Publication, SEBU6400, "Cat Gas Engine Lubricant, Fuel, and Coolant Recommendations".