G342C NATURAL GAS ENGINE Caterpillar

Fuel, Lubricant And Coolant Specifications

Usage:

Fuel Specifications

Dry Natural Gas

Dry natural gas is a mixture of Methane, Ethane and not more than 5 percent Propane and a fractional percentage of Butane. It can also be referred to as commercial pipe line natural gas.

The reference to "dry" refers to the absence of liquid petroleum products such as liuid Butane or liquid Propane.

The BTU content of dry natural gas can vary. Caterpillar gas engines are factory adjusted with a dry natural gas having a low heat value (LHV) of 905 BTU/feet³ (33.72kJ/I).

NGO

Oil recommendation is determined by the gas and the intake air conditions.

Units operating on processed natural gas should use oils formulated with additive systems containing between zero and 0.5% maximum slufated ash and meet the CB (Supp 1) clasification. The oils are composed of ashless dispersants and either organo-metallic (provided they do not contain barium, calcium or magnesium) or completely ashless oxidation inhibitors. Your oil supplier knows which oils meet these requirements.

Sour gas generally refers to fuels containing sulfur compounds, primarily hydrogen sulfide. (Gases containing no sulfur compounds are referred to as "sweet gas".) Severe damage to engines can occur if this contaminant is ignored. Water vapor and sulfur oxides formed during combustion can combine to form sulfuric acid compounds. Internal components, particularly valve guides, piston rings, and cylinder liners will be subjected to corrosive wear shortening engine service life.

If analysis of the fuel shows the concentration of hydrogen sulfide to be greater than 0.1% by volume, the fuel should be treated (scrubbed) to lower the H₂S level below 0.1%. When using fuels with 0.1% H₂S or less, the following preventive steps should be taken:

1. The coolant outlet temperature should be maintained between 88°C and 93°C (190°F and 200°F). Temperature rise across the engine should be no more than 9°C (15°F), and a 6°C (10°F) rise is desirable. Water and sulfur oxides are formed during combustion and will condense on cylinger walls at low temperature. The higher jacket temperature will minimize the amount of condensation.

Engines equipped with inlet control cooling systems will maintain outlet temperatures in the 88°C to 93°C (190°F to 200°F) range. Engines with outlet control cooling systems may require additional external controls to maintain 88°C to 93°C (190°F to 200°F) outlet temperatures.

2. The temperature of the oil in the sump should be maintained high enough to prevent water from condensing in the oil. Normally maintaining the jacket water outlet temperature at a minimum of 88°C (190°F) will accomplish this.

3. Establish an oil analysis program to assure oil change periods are not extended byond safe limits and that other problems are not overlooked. Caterpillar dealers are capable of establishing and conducting such programs.

4. A CD grade oil with less than 1% sulfated ash can be used instead of oils normally ued in natural gas engines. CD oil has a higher TBN (which indicates its ability to neutralize acids formed from products of combustion of sulfur compounds) than normal gas engine oil.

5. Where it is possible to start the engine on sweet gas, the engine should be brought up to operating temperature on sweet gas, then switched to sour gas. The procedure should be reversed when shutting the engine down.

Consult your Caterpillar dealer if other conditions exist.

Lubricant Specifications

MPG

Use Multipurpose-type Grease. Multipurpose-type grease which contains 3% to 5% molybdenum disulfide is preferred. NLGI No. 2 Grade is suitable for most temperatures. Us NLGI No. 1 or No. 0 Grade for extremely low temperatures.

Coolant Specifications

Use a mixture of approved fill water, antifreeze and cooling system conditioner.

"Know Your Cooling System," Form SEBD0518, can provide more detailed specifications.

Fill Water

Always add conditioner to water. Never use plain water only.

Antifreeze

Use ethylene glycol-type antifreeze. Use the correct amount to provide freeze protection to the lowest expected operating environment.

Coolant Conditioner (Liquid)

Use Caterpillar liquid cooling system conditioner or equivalent. Follow the instructions on the container.

On a new or reconditioned engine add 1 pint (0.5 liter) of Caterpillar cooling system conditioner for each 4 U.S. gallons (15 liters) so that the cooling system will have a 3% to 6% concentration of conditioner.