What Is an Oil Pressure Sensor?

Updated on January 25, 2019

The Car's Oil System

Inside your car's engine, motor oil plays three vital roles: lubricating, cooling and cleaning. A problem with any one of these three can have major consequences for the engine. Before we can understand the role of the oil pressure sensor, we need to understand how oil works inside the engine.

An oil pressure sensor
An oil pressure sensor | Source

Lubrication for Beginners

To begin with, consider lubrication. Inside the engine, power is converted into rotary motion which is used to drive the car forwards (or backwards). In very simplified terms, when a mixture of gasoline and air ignites in the combustion changer, it forces the pistons up and down. The up-and-down motion of the piston is then converted to rotary motion by the turning crankshaft. In this simple case, we have two sets of components that need lubricating.

The first of these, the pistons, need oil to prevent them from coming into direct contact with the cylinders in which they slide up and down. Even though pistons and cylinders are allies in the car's engine, and they are tough, if they were to rub against each other they would soon become damaged, and they would be much less efficient. That is why oil is needed to provide a cushion for them to glide over. Oil also lubricates the bearings inside the crankshaft. Again, this keeps the bearings from wearing out and increases the efficiency with which they drive the crankshaft and change the linear motion coming from the pistons into the rotary motion that turns the wheels.

Cooling the Engine

Next, we can consider cooling. The engine gets extremely hot. Most cars have a main cooling system using a mixture of water and antifreeze, known as coolant. Coolant circulates around the engine, penetrating through holes drilled in the engine for this purpose. As it travels, it heats up and in this way extracts some of the heat from the engine. Then it is pumped to the radiator, where it spreads over a very large surface so it can be cooled by the airflow coming in from the grill.

However, the coolant cannot actually go inside the engine. Water is a poor lubricant, and it does not mix with oil; this is why oil is also used to cool inside the engine where coolant cannot go. In order to lubricate, the oil has to coat all of the surfaces where components might otherwise touch each other. It spreads over a large area inside the engine. Surface area is critical in the transfer of heat; the larger the surface area that is covered, the more heat can be absorbed. In this way, motor oil removes a lot of heat from inside the engine before falling down into the oil sump where it cools off before being recirculated. Some high-performance engines have a dedicated unit called an oil cooler just for this purpose.

Replacing the Oil Pressure Sensor

How Motor Oil Cleans

Finally, modern motor oils contain additives to help them clean the engine. Without these cleaning chemicals, a black slurry would collect on the internal surfaces, which would do two things. First it hinders the flow of oil and therefore reduces the oil pressure. Second, it decreases the area that the oil comes into contact with and therefore decreases the amount of heat the oil can extract. It is possible for an engine to get so hot that its parts become welded together. This is the dire consequence of a lack of oil or a lack of oil pressure. Most motor oils are called synthetics because they are man-made. All this really means is that they are man-made from a base of mineral oil; pure synthetic oil is extremely expensive and only used in industrial applications. However, because oil is so important, it’s a good idea to buy the best motor oil you can afford. Don’t choose a cheap synthetic oil change to save a few dollars; it could cost a lot more in the long run.

Under Pressure!

For all of this to work, the oil has to be kept under pressure. It cannot just trip through the engine at its own leisurely pace; it must move quickly. Keeping the oil pressurised provides the necessary resistance needed to lubricate the moving parts. The pressure keeps it from being swept away by the forces in the engine trying to push these components against each other. Oil also needs to be moved to make sure it can extract enough heat. A constant supply of core oil is needed to do this.

As the oil is circulated by the automotive oil pump it passes through an engine oil pressure sensor, also called an oil pressure sender. This sensor checks whether the pressure is within the manufacturer's recommended limits and sends a signal to the oil pressure gauge or oil pressure warning light on the dashboard to notify the driver that there is a problem.

Any problems relating to low oil pressure should be fixed immediately. Never continue to drive when your car is too hot or if the dashboard says it has low oil pressure. If in doubt always seek professional advice.

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.


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    • profile image

      Ayodele Ganiyu Olawale 

      10 months ago

      I want to have online training on this platform,

      What is the requirement please . My mail address ; ayodeleolayeni619@gmail.com

    • profile image


      4 years ago from Nice, France

      Very informative article about oil pressure sensors !

      But it will be better if you'll write articles about low oil pressure or oil pressure senders/switches,Because internet is full of answers about them,on forums blogs and etc.

      And there is no quality information.

      For people whos cars have problembs about low oil pressure or etc.there is one site where you can get informated or buy right parts http://caroilpressure.com/

      Before we need to wait DennisRuskin to post another great hub.

      Sincerly, Dubincorp


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