A/C Pressure - Cycles High Then Low?

TONS2000

MEMBER
JEEP CHEROKEE

I was trying to measure my A/C pressure in my 2001 Jeep Grand Cherokee Limited with a V8 and the engine would cycle casuing the A/C pressure to read high (over 45), then go low (under 20). Which pressure is the accurate one for gauging if my freon is low. Thanks in advance for any advise.

1 Reply

DEMEARSJR

MECHANIC
110 POSTS

When measuring A/C pressure in a vehicle, it's important to consider a few factors. The A/C system operates by cycling the compressor on and off to maintain the desired temperature. The pressure readings can vary depending on whether the compressor is engaged or not.

Typically, the accurate pressure reading for gauging if the refrigerant (freon) is low is taken when the compressor is engaged and the A/C system is running. This reading is known as the "static pressure." When the compressor is off, the pressure will equalize and may show a higher reading, while when the compressor is on, the pressure will drop due to the system actively cooling.

To get a reliable assessment of your A/C system's refrigerant level, you may need to monitor the pressure when the compressor is engaged and the A/C is running. This can be done using a set of A/C gauges designed for automotive applications

This guide can help

https://www.2carpros.com/articles/air-conditioner-how-to-add-freon

Please let us know if you need anything else to get the problem fixed.