Machinery Lubrication

Machinery Lubrication May - June 2018

Machinery Lubrication magazine published by Noria Corporation

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Page 62 of 80

Oil pressure is one of the most important pa ra meters in a n engine. When your vehicle's oil pressure light comes on or the pressure gauge reports a lower than normal reading, it could signal a major problem. Unfortunately, you won't know whether the issue is serious, so the best course of action is to simply turn off your engine. To help provide a better understanding of engine oil pressure, this article will explore the possible causes of low oil pressure and the most effective ways to remedy it. Why Oil Pressure Is Important An engine's lubrication system is essentially formed by the pump, oil filter, lubrication lines and hardware. e pressure in the system is gener- ated by the resistance that the oil must overcome in the lines to reach the lubricated components. A pump is used to force lubricant through the system. When an engine is in the design stage, the pump is engineered to generate the required pressure and flow to allow the lubricant to circu- late to the most remote component. When the oil pressure is low, it indicates something is not working properly. It also means there likely is not enough lubricant moving through the system. Keep in mind that lubricant starvation will lead to metal-to-metal contact and machine failure. Depending on the severity of the situation, an engine can fail in a couple of hours or even a few minutes. e repair could also be costly, with most of the engine needing to be replaced. Viscosity's Impact Viscosity affects oil pressure. If you were to pour oil on an inclined surface, it would f low downhill due to the force of gravity. e higher the viscosity, the slower the lubricant will flow. Viscosity can be defined as resistance to flow. Lubricant viscosity varies with temperature, decreasing when the temperature rises and increasing when the temperature drops. ere- fore, engine oil viscosity will be dependent on the engine's ambient temperature during startup as well as its normal operating temperature. ere are two common ways to measure viscosity. e first involves allowing oil to flow through a capil- lary tube and recording the amount of time it takes to flow from one point to another. Viscosity can also be measured by putting the lubri- cant in a calibrated cup and stirring it. The higher the viscosity, the more difficult it will be to stir. is resistance is calculated by a lab torque- meter. Tests are performed at precise temperatures for consistent results. Most vehicle owners are familiar with the viscosity grades developed by SAE International, such as SAE 30, SAE 40, etc. ese standards, which are based on the measurement systems described above, simplify Causes of Low Oil Pressure in Engines 58 | May - June 2018 | www . Automotive BACK PAGE BASICS Alejandro Meza | Noria Corporation "When the pressure gauge detects low oil pressure, be aware that it may be real or just an inaccurate reading."

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