MOTOR GP-AIR STARTING 6N4147 - Caterpillar

This article is to be used as a general guide for many different types of engine failures. Some of the information in this article may or may not apply to a specific failure on your engine.
Many times reports of engine failures do not give the correct and/or complete information about the cause of the failure. Because of these reports it is difficult to know what action to take to prevent the same kind of failure in the future. This article gives a troubleshooting procedure and recommendations on what to look at, measure and photograph. Use of the information in this article will increase the quality of the reports, so better preventive action can be taken.
GENERAL RECOMMENDATIONS
1. Make an identification of which component was the first to be damaged in the sequence of events.2. Use a step by step procedure to find out what caused the failure of the first component.3. The use of earlier experiences as an example is good, but it can also cause you to come up with some wrong conclusions. Two failures can look the same, but in fact, the cause can be very different.4. Discuss the failure with someone else. A second opinion can be used to check your analysis of the facts.5. Make use of the Caterpillar publications that are available on such topics as bearing failures, gear failures, turbocharger failures, etc. The Service Information Retrieval System (SIRS) has a complete list of these publications on the SIRS Index microfiche titled, "Special Publications Such As Guidelines And Failures."6. Always make a note of and photograph any unusual conditions that are found. Also, mark the component's position in the engine.INFORMATION AND HISTORY
1. Get the serial number, arrangement number, and service meter units (SMU) or miles operated for the engine.2. Check the engine's history (earlier service information).3. Get the customer's description of the failure.4. Look at the general condition of any components the engine was used with. Some examples are radiator, transmission, power take-off, etc.5. Make a record of the brand and Engine Service Classification of the oil. Get samples of new and used oil. Take an oil sample to check for debris and the content of fuel and water. Also, check the alkalinity of the oil. If it is available, check the Scheduled Oil Sampling (S.O.S.) history for the engine. Infared analysis can be used to check the percent of soot, oxidation and sulfur in the used oil.6. If the oil filter has already been removed, obtain it so an analysis of it can be made.7. Check the sulfur content in the fuel.8. Check the owner's maintenance records for the oil and filter change periods, oil consumption and oil level. Check for any unusual oil conditions. Look for foaming, or oil that is too dirty or too clean for the time the oil has been in use.9. Check the applications and conditions the engine was used in. Look for indications of high altitude, overheating, overloading, overspeeding, high inlet temperatures, etc.ENGINE DISASSEMBLY
External Condition
Check the external