631E Series II Wheel Tractor-Scrapers S·O·S Services Oil Analysis Caterpillar

Note: DO NOT USE ONLY THIS SPECIAL PUBLIAVSION AS A BASIS FOR DETERMINING OIL DRAIN INTERVALS.

Evaluation of oils to determine their condition as they are used in the engines or machine compartments is a powerful tool to indicate the engine or component performance and to support durability and reliability that has been designed into these engines and machine components.

AVSpare has developed a maintenance management tool that evaluates oil degradation and detects the early signs of wear on internal components. The Cat tool for oil analysis is called S·O·S Oil Analysis and the tool is part of the S·O·S Services program. S·O·S Oil Analysis divides oil analysis into four categories:

• Component wear: elemental analysis of the oil evaluates wear metals and contamination in the oil. Wear metals analysis allows the evaluation of wear of lubricated components or engines.

• Oil condition: determines if the oil has degraded due to chemical or thermal stresses. This analysis includes oxidation, nitration, sulfation, viscosity, soot and if needed total acid number and/or total base number.

• Oil contamination: testing of harmful contaminants that may have entered the oil including dirt, water, fuel and coolants. Oil contamination can cause wear and damage of engine and lubricated components.

• Oil identification: this analysis ensures that the appropriate quality of oil is used and that the right oil is used in the right compartment. The wrong oil in a compartment can severely damage major components.

These four types of analysis are used to monitor the condition of your equipment, and to help you identify potential problems. A properly administered S·O·S Services Oil Analysis program will reduce repair costs and the program will lessen the impact of downtime.

The S·O·S Oil Analysis program uses a wide range of tests to determine the condition of the oil and the condition of the lubricated compartment. Guidelines that are based on experience and a correlation to failures have been established for these tests. A trained person at your Cat dealership should make the final analysis.

Oil analysis is one of the diagnostic tools to determine engine health. Oils that are within the limits given by the guidelines may not indicate all engine health issues. Under certain conditions, including, but not limited to severe operating conditions, oils that are within the limits given by the guidelines may require changing early.

Note: Cooling system problems will also reduce the life of engines, transmissions, and hydraulic systems. S·O·S Coolant Analysis together with S·O·S Oil Analysis provide a complete and accurate method for monitoring the health of all machine systems. Refer to the S·O·S Coolant Analysis information in this publication. A properly administered S·O·S Services program will reduce repair costs and lessen the impact of downtime.

Refer to the “Contamination Control” article in this Special Publication for recommended fluid cleanliness targets.

Note: Most oil analysis programs do not detect larger particles in the oil sample. Some failure modes only produce larger particles. Oil analysis alone will not always detect an impending failure. Oil filters should be sectioned and inspected for the presence of visible particles.

The engine oil consumption must be measured and recorded. A significant increase in oil consumption can indicate a problem with cylinder pack deposits or components. Additionally, oil additions dilute wear metals and other contaminants. Oil analysis results may become inaccurate.

Consult your Cat dealer for complete information and assistance about the S·O·S Oil Analysis program.

Obtaining S·O·S Oil Samples

Before you obtain an S·O·S oil sample, operate the machine until the oil is warm and the oil is well circulated. Then obtain the S·O·S oil sample.

In order to obtain a good oil sample, do not take the oil sample from the drain stream. The drain stream method can allow a stream of dirty oil from the bottom of the compartment to contaminate the sample. Likewise, never dip an oil sample from an oil container or pour a sample from a used filter.

There are two ways to obtain S·O·S oil samples. The following methods are listed in the order that is preferred:

• Use an in-line sampling valve for pressurized oil systems.

• Use a sampling gun that is inserted into the sump.

Use of the in-line sampling valve is the preferred method. This method provides samples that are less likely to be contaminated. Whenever you obtain the samples, obtain the samples from the same point. The samples will be more representative of the oil that is in the system.

Normally, the oil sample is taken at low idle. If the flow rate is too low, increase engine speed to obtain the oil sample.

In-line sampling valves cannot be used on nonpressurized oil systems such as differentials and final drives. Use of the sampling gun is the preferred method for nonpressurized oil systems.

Refer to the Operation and Maintenance Manual, "Maintenance Interval Schedule" for the proper interval.