Automotive Air Conditioning Information Forum (Archives)

ScottsGT on Sat June 02, 2012 1:04 PM

Year: 1995
Make: Ford
Model: Mustang GT
Engine Size: 5.0
Refrigerant Type: R134a
Ambient Temp: 80
Pressure Low: 66
Pressure High: 70-150

Go easy, I'm a noob here! But last year I had a leak on my high pressure side where the gauge connects. I replaced the fitting and did the quick fix of dumping in 2 lbs using a cheap set of gauges from Autozone.
Our first hot days this year were last week and in the mid 90's. Had the usual issue of not cooling good until out on the highway. So I picked up a quality set of gauges and now I'm getting a reading of 66 on the low side and the high side is cycling off and on with pressures of 70-150. As soon as pressure hits 150, comp. shuts off. Soon as it hits 70, cycles back on.
This is all at idle speed around 900 rpms. My low side tells me that it's not a low freon problem, but maybe a compressor on the way out?
Thoughts?

mk378 on Sat June 02, 2012 3:23 PM

Are the hand valves on the manifold closed? They need to be to measure pressure. If they are open, the high side is connected to the low side and neither gauge will read correctly.

ScottsGT on Sat June 02, 2012 3:56 PM

Yes, valves were closed.