LO 10-7 Outline lubrication system maintenance and service procedures
1. Maintenance of Lubrication Systems
1.3. Oil Change Interval
LO 10-07: Outline lubrication system maintenance and service procedures. |
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Oil Change Interval Oil change intervals are based on the operating conditions an engine encounters and the amount of fuel consumed. Several formulas are used to calculate the correct service interval, but generally, every 45 gallons (170 L) of fuel consumed by the diesel engine produces enough contaminants to use up to 1 quart (1 L) of oil. The recommended oil change interval is calculated by multiplying the quantity of oil in the oil pan by the number of barrels of fuel burned (45 gallons [170 L]). This means a vehicle with 7 miles per gallon (mpg; 3 km/L) fuel consumption, with an oil pan capacity of approximately 40 L (close to 9 gallons), will need to be changed at 12,600 miles (20,117 km). Extending service intervals beyond this can be achieved using good-quality lubricating oils, such as synthetics, that resist oxidation and acid formation. Filters that remove oil life-limiting soot are also needed. An engine ECU can be configured to prompt the driver to have the engine oil changed. A maintenance monitor light in the dash can alert the driver when oil is at the end of its service life. Technicians need to reset the monitor after service Figure 55. Stop-and-go urban traffic, heavy loads, cold weather, extended idle, etc., are severe operating conditions that shorten the oil service interval. Moderate temperatures and steady-state driving conditions on a highway are normal service conditions that extend oil life TABLE 10-7. The best practice to extend oil change intervals is to use engine oil sampling analysis to determine the levels of solids, TBN, and limits of oil oxidation. |
FIGURE 10-55: This Caterpillar engine has software that enables technicians to activate a dash light to alert the driver when a service is due. |
| TABLE 10-7: Maximum Oil Drain Intervals | ||||
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| Technicians Tip | ||
| Oil must be changed when soot levels reach a maximum of 3–5%. Failing to change oil at these levels will cause excessive wear and soot-thickening of oil. Soot-thickened oil does not move well through oil passages, especially when cold. Soot is also an abrasive that accelerates engine wear. |
| Technicians Tip | ||
| Engines built in and after 2007 are not permitted to allow oil carryover to the atmosphere. Many engines use a closed crankcase system, which means the crankcase has no direct connection to the atmosphere. When draining oil from these engines, remove the oil fill cap during oil drain to help the oil drain faster. |
| SAFETY TIP | ||
| Remember, hot engine oil can easily exceed the temperature of boiling water. Hot engine oil can scald, and extreme care is necessary to prevent injury when performing. Use insulated gloves when removing oil pan drain plugs. |
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