The mechanical oil pressure gauge on your car’s instrument panel is used to tell you the pressure of the oil flowing around the engine. It is critical to monitor the pressure because if the pressure falls to low the oil can no longer do its job. There are three main tasks the oil has to fulfill inside the engine unit.
The first and most important job is to provide lubrication. The engine is full of moving parts which come into contact with each other under extreme conditions of heat and pressure. Oil acts as lubricant between these moving parts preventing them from touching directly, for if they did they would quickly wear each other away. Given the temperature inside the engine it is also possible that these parts would actually friction weld themselves together.
This is also where the second purpose of oil comes into play. Cooling is needed to prevent overheating and damage. Because the oil circulates around the engine all of the time and covers every surface of the engine it provides a useful way to absorb surplus heat and carry it away to the oil pan. This is the reservoir where the oil collects after it has been through the engine. Because the oil pan is underneath the car, as the car moves along it is cooled, therefore hot engine oil entering the oil pan is naturally cooled. Some cars also have an oil cooler component to assist with this process.
The third job of oil is to clean. Because oil coats the engine entirely it inhibits oxidisation because the metal cannot come into contact with oxygen. Oil also contains cleaning additives to help prevent the build up of sludge.
Once we understand the role of oil in the car we can appreciate the need to keep a constant eye on the autometer oil pressure gauge.
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