LO 10-5 Identify and describe the types, functions, construction features, and applications of diesel engine lubrication system components

1.1. Oil Pan

Oil Pan

The function of the oil pan is to store an adequate supply of oil for the lubrication system Figure 25. The deeper portion and larger volume of the pan connected to the oil pump pickup is called the sump . While more than enough oil is available in the oil pan to supply the lubrication requirements of the engine, excess oil is needed to distribute contaminant loading of lubrication oil and to provide a reserve capacity to compensate for oil consumption. Oil volumes pumped by the engine can easily recirculate all the oil sump capacity in under a minute. With increased oil pan capacity, longer intervals between drain periods can be set by the manufacturer. The location of the oil pan provides some cooling of engine oil, which is normally at temperatures above coolant operating temperature. Excess oil capacity allows the oil to remain in the pan longer and cooler. An oil pan may be made of fiberglass, stamped steel, or aluminum Figure 26. Significant engine noise originates from the oil pan, so it may be covered in sound-insulating material.

FIGURE 10-25: The plastic oil pan, or sump, holds in excess of 11 gallons (40 L) of oil. The plastic material helps dampen engine noise.

FIGURE 10-26: The aluminum oil pan of this off-road diesel contains baffles to prevent the sloshing of oil. Aluminum helps reduce engine weight and improves heat transfer from oil.

As mentioned, the sump is the deepest part of the oil pan where the oil pump pickup tube is located. Depending on the chassis configuration, the sump may be located at the rear, front, or middle of the engine to accommodate suspension-of-frame component clearances. Two drain plugs may be used in the sump and at the other end of the oil pan to ensure that as much contaminated oil is drained as possible.

An oil dipstick measures the level of engine oil when the engine is off Figure 27. A windage tray may also be incorporated into the oil pan or just above the pan. Windage trays separate the crankcase from the oil pan reservoir to prevent the crankshaft from whipping engine oil stored in the pan Figure 28. The primary advantage of the tray is that it can increase fuel economy by as much as 1–2%. The tray also prevents customer complaints in LD and MD engines, such as engine thumping and stumbling during cornering or braking, when oil can surge up into the crankcase area. Additionally, the oil-level sensor used in the lower pan warns the driver if oil levels are dangerously low.

FIGURE 10-27: The engine oil dipstick measures the level of oil when the engine is off. The oil level should be between the hash marks. Overfilling will cause seals to leak and aerate the oil.

FIGURE 10-28: The windage tray from a Mack MP7 engine. A windage tray prevents oil from interfering with crankshaft motion and causing oil foam.