Cat Gas Engine Lubricant, Fuel, and Coolant Recommendations Caterpillar

The use of gases that have hydrogen sulfide can damage the engine. Products of combustion (water vapor and sulfur oxides) form sulfurous acid and sulfuric acid. Sulfur reacts easily with bright metals such as copper. Therefore, oil coolers are usually the first components that are affected by the acids. Other engine parts that are attacked by the acids include the following components:

• Fuel valves

• Valve mechanisms

• Piston pin bushings

• Piston rings

• Cylinder liners

• Exhaust manifolds

• Aftercoolers

Various devices can reduce the content of hydrogen sulfide. Examples are chemically active filters, reactive beds, and solutions. The performance of the devices deteriorates as the reactive chemicals are depleted. The devices must be serviced or replaced in order to maintain effectiveness.

Take the following precautions even if the gas is treated in order to reduce the level of hydrogen sulfide. This will help to protect the engine against intervals when the devices for treating the fuel deteriorate. Even brief intervals of operation with high sulfur fuels can damage the engine, unless precautions are taken.

• Use an engine configuration that has a fuel system that is designed for sour gas and a positive crankcase ventilation system..

• Maintain the temperature of the coolant outlet to a minimum of 110 °C (230 °F). Lower jacket water coolant temperatures permit water vapor and hydrogen sulfide to condense on the cylinder liners. Higher temperatures will reduce this condensation. Do not allow the rise in temperature across the engine to exceed 8.3 °C (15 °F). A rise in temperature of 5.6 °C (10 °F) is preferable.

• Establish an oil analysis program in order to ensure that the oil change intervals are not extended beyond the condemning limits of the oil. The oil analysis will also be able to detect other problems that may occur.

For additional information on gaseous fuels and on treatment of the fuel, refer to the following publication:

• Special Publication, LEBW4977, "Gaseous Fuels - Application and Installation Guide"