Signs Your Car A/C Needs Freon


Freon is a crucial element for automobile A/C systems. It is compressed via the compressor which causes the pressure to increase along with the temperature. The heated Freon is then transferred through the coils inside the air conditioning unit, lowering the temperature and transforming the substance into liquid. Below are some signs your car A/C needs Freon. 

Low Freon Symptoms

One of the first things you’ll notice is that your A/C clutch won’t engage. This is because the Freon levels have become so low that the compressor can’t pressurize. Other indications of inadequate Freon include:

  • Lower gauge readings
  • Signs of leakage
  • A/C won’t blow out cold air
  • Sight glass

Lower Gauge Readings

To check your gauge readings, you’ll want to connect your air conditioning manifold gauge with the low or high service port. Make sure your gauge fits properly by linking a red colored gauge hose with a service port on the high side with the quick release-based setting. The blue gauge hose must be connected to the server port’s low side. 

For accurate readings activate the blue and red gauges once the car’s A/C and engine have been turned off. The readings should show a psi between 80 and 105. When the A/C is run at the highest setting, its high side should have a psi between 200 and 350, and on its lower side, the reading should be between 25 and 35 psi. Lower readings than this are an indication of insufficient Freon levels.

Signs of Leakage

Leaks will often be visible, because Freon consists of oil which enables it to provide lubrication for the compressor, and in a liquid state will resemble grease. To find a potential leak, you’ll need to inspect multiple A/C components, such as its service ports, front shaft, and pressure lines.  If you see liquid stream or film on any of these components there is a good chance you’ve got a leak. You can test it by wiping away the stream or film and then checking to see if it reappears. 

A/C Won’t Blow Out Cold Air

This is the most obvious sign that you’ve got a problem with the Freon levels. Either the vents won’t blow out air at all or the air you’re getting is hot. The reason this happens is that the inadequate Freon levels make it impossible to correctly pressurize and then circulate inside the system.

Sight Glass

Some vehicles come with a component called a sight glass. This auto part enables a viewer to identify Freon transfer via a high-pressure-based line. If your Freon levels are normal, you will see a clear substance transiting the line, but should Freon levels be too low, you’ll see bubbles. A total lack of movement is a sign that the vehicle has no Freon in it whatsoever.

If your A/C system is exhibiting any of the signs above, you’ll want to stop using it immediately. Continuing to run the air conditioning while the Freon levels are low can cause long-term damage that can be costly to repair.