In addition to submitting the required samples to the NOAP laboratories, you can use the ship-board diesel engine lubricating oil test kit to take samples and perform tests on your ships diesel engine lube oil (9250). The kit provides a quick and accurate means you can use to check used oil for fuel dilution, viscosity, and acidity to determine if the oil is within the specified limits. Oil color change is common in diesel engine lube oil after a few hours of use. The change in color is due to the suspension of fine particles of unburned carbon (soot) that accumulate in the oil. Darkening is not a definite indication that the oil has lost its lubricating properties. Diesel engine lube oil should not be drained solely because of color change.

Water in lubricating oil can usually be detected by the cloudy appearance of an oil sample taken from an operating engine or by small droplets of water that may separate in a sample bottle. A small quantity of free water in the lube oil in a diesel engine should cause no difficulty because it will change to steam and pass into the exhaust system as the engine reaches normal operating temperatures. Any salt accumulation in the oil will be monitored through NOAP. However, when serious water contamination exits, such as free-standing water in the bottom of the sample bottle or if the oil has a cloudy appearance, the oil should be drained and replaced with fresh oil after the source of the leak has been repaired. The effectiveness of any lubricating system depends on the quality of the lubricant and the condition of the principal parts of the engine. The life of a diesel engine is remarkably long provided the engine is adequately lubricated.

Effective lubrication in turn depends on timely completion of required checks, inspections, and maintenance procedures. For additional informa-tion, refer to the Naval Ships Technical Manual, chapters 233 and 262.