How an Oil Pressure Gauge Works

An oil pressure gauge is an essential part of the car and acts as an indicator of your car's engine's health. This instrument tells you about the well-being of your engine and acts as an early warning system.

By Carandbike Team


1 mins read


Published on February 4, 2022

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  • The gauge tells you about any problems in the engine in advance.
  • The oil pressure gauge works as a monitor to check the oil pressure.
  • The oil warning light has a sensor and provides indications.

The gauge tells you about any problems in the engine and gives you advanced notice, saving you from an expensive breakdown. If any, you can investigate the problem and save a lot of time, effort, and money. 

How Does an Oil Pressure Gauge Work?

The oil pressure gauge works as a monitor, and its job is to see the oil pressure in the main oilways near the filter and the pump. The engine block has a tapping and either an oil pipe or a sensor screwed into it.


Photo Credit: www.mecatechnic.com

The oil warning light has a sensor and is screwed into the T-piece or the union. It doesn't matter if the car has a fitted oil pressure gauge or not. 

The mechanical gauges work because the engine's pressure forces the needle into the dial. On the other hand, electrical gauges work with a sensor that produces variable resistance and is screwed into the engine block. This affects the circuit that has the sensor and the gauge through the current that passes through it.


A mechanical oil gauge

Mechanical oil gauges don't use wires but instead use pipes. Technicians believe that this not only creates a trustworthy reading compared to wires but also creates risks. Instead of using electrical currents to measure resistance, the mechanical gauge funnels oil into the small pipe simultaneously at the same pressure at which it flows in the engine. The oil pipe is placed in such a way that it is away from anything that could damage it, as it could lead to the spilling of oil if the pipe is damaged. Mechanical gauges require more attention and delicacy than electric gauges.


Photo Credit: www.vdo-gauges.com

Electric gauges

A fused power supply provides electric current to the gauge, and the current is supplied from printed tracks or one of the wires behind the dashboard. A wire-wound coil that is mounted within or around the needle's pivot passes the current and produces a magnetic field. This field is responsible for moving the needle across the gauge. The amount of current decides which reading to give and how far the scale goes. It depends on the gauge's return wire's resistance, which you will find is earthed to the engine block with the help of a sensor. 

Oil pressure decides the sensor's resistance, and oil enters the sensor's end by pushing against a diaphragm screwed into the engine block. 

The Difference 

The electric gauges are easier to route and are less bulky. The electric gauges get easily integrated into the modern circuits that modern cars have.

Mechanical gauges are not so common compared to electric ones. The problem with a mechanical gauge is that it can get very messy if it gets damaged. 

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