Automotive Vacuum Pump Information

What are vacuum pumps used for?

When servicing automotive air conditioning systems, it is often necessary to pull a vacuum on the system in order to remove any air and moisture from the system. Air and moisture will create leaks and will destroy your AC system.

How do vacuum pumps work?

Vacuum pumps lowers the pressure inside of the system to below atmospheric pressure. This in turn causes water vapor to boil off and exit the system.

Do I need to change the oil on a vacuum pump?

As the pump extracts contaminants from the system, they end up in the pump's oil. Dirty oil will hinder performance so be sure to change the oil frequently.

Types of Vacuum Pumps

Vacuum pump sizes are measured primarily in CFM (Cubic Feet per Minute) which is a gauge of the speed of the vacuum flow. Generally, the higher the CFM, the deeper the vacuum a pump can pull, and the faster it will happen.

Two common vacuum pump types are single stage and double stage. Double stage pumps are defined by their use of a double rotor and double vane set. It is similar to having concurrent pumps where the initial stage stage produces a moderate vacuum and the second stage pulls the exhaust of the initial stage to deepen the vacuum.

Single stage pumps will work fine for DIY, but professionals generally rely on 2-stage pumps to save time.

Vacuum Pump Brands

Some of the more common brands of vacuum pumps are Robinair, FJC, and Mastercool.