There are a range of pressure testers used in the automotive industry. Each of them is used to provide information about the potential condition of various systems and components.
All gauges consist of a measurement scale from which a reading is taken. Depending on the type of fitting on the gauge, it is normally fitted to the vehicle component via a pipe or tube. Instructions provided with the gauge will describe how to take a correct reading. These should include the specific operational circumstances that the reading should be taken under, in order to interpret correctly the condition of the item being tested.
Most gauges are designed to read "zero" at atmospheric pressure (14.7lbs/sq inch or 1 Bar at sea level) as a base measurement.
Some types and applications:
Tire pressure gauges 1:
This type of gauge is the one most familiar to most people. Tire pressure gauges are normally part of a tire inflation device and are used to ensure that the air pressure inside the vehicle tires is maintained at the recommended setting.
Tire pressure gauges 2:
Gauges that only measure, that is, they just check the pressure without being able to inflate as well, are also quite common. The illustration on the left is an example of this type, known as a 'pencil-type' pressure gauge.
These gauges are a particular type pressure gauge that measures "negative" pressure below atmospheric pressure. They are normally used to determine an engine's general operational condition. Depending on the reading a number of engine faults can be identified.
These gauges are used to measure the compression pressures inside an engine cylinder and can identify overall condition and pressure leakage situations that could be caused by a range of engine faults.
Cooling system pressure gauges:
These are used to identify faults in cooling systems and components like pressure caps.