What Is The Correct Auto A/C Pressure?

In the past, auto A/C pressure was challenging to measure and the tools used to obtain it were costly. Thankfully, technological advances and the wide availability of car parts stores have made it a lot easier to obtain this information.

Refill Cans

One tool that can help you determine the right A/C pressure is a refill can. They can be found at most car parts dealers and come with pressure gauges that will assist you in understanding your system and the amount of refrigerant you’ll need to dispense. The gauges are quite accurate and very cost effective, and are primarily used to determine the pressure on the low side.

Measuring The High Pressure Side

In addition to the low pressure side, you should also get measurements of the high pressure side. The reason for this is because the A/C system is divided in two regarding pressure. The pressure that exists between the condenser and compressor is high, whereas the pressure between the evaporator and expansion valve is low. The refill cans sold by auto dealers are pressurized so that it is easier to push fresh refrigerant inside the system. To get the most out of these cans, you will want to attach them to the side with the low pressure which will allow you to determine the measurements shown on the gauge.

However, for the high pressure side, you’ll need something different. The reason for this is because the elevated pressures mean that specialized connections and hoses are required as well as a gauge that will prevent the refrigerant from being released into the surrounding environment. The tools most auto experts will recommend are air conditioning manifold gauges.

How To Read A/C Pressure

Once you have a safe way of measuring the A/C pressure, you have to know how to interpret the readings. Pressures will vary from one vehicle to another, and will also be influenced by ambient temperatures. In other words, warmer environments will result in higher pressure readings. There are charts available which you can reference to determine specific R134a pressures.

If you detect low pressure readings on the side with low pressure, this means you probably have a leak, which is common in auto a/c systems. It might also be an indication of clogging. If you detect low pressure on the side with high pressure, it means that either your refrigerant levels are too low or you have a problem with the compressor. If the pressure on the high side is elevated, it means that the system is either overfilled or it might be clogged.

Most issues involving the A/C will need a system refill, repair and vacuum. However, if you have a leak, you will want to add a conditioner and stop leak to the port that has low pressure. This will get your air conditioning back to working form so you can enjoy cool and high quality air.