Need Help Troubleshooting System

JoJoDaClown on Sat April 14, 2012 9:11 PM

Year: 2008
Make: GMC
Model: Acadia
Engine Size: 3.6
Refrigerant Type: 134a
Ambient Temp: 70
Pressure Low: 0-45
Pressure High: 55
Country of Origin: United States

A few weeks ago, the vent temperature was much warmer than it should have been (it was the first time setting the temperature cold in the car since summer) probably was 40F vent and 70F Ambient. We had the same problem a year prior and topped the system off and it ran great for months. So 2 weeks ago I bought a can of 134a and a can of leak sealer (10oz 134a, 2 oz sealer, I think). Put in the full can of sealer and half of 134a can. I filled until (at 2000 RPM) the low side was 20 psi before compressor cycled off, and high side was between 150 and 180 psi.
We were driving today, and vent temp was warm and muggy. ambient was 69F and vent was probably about the same. Compressor is cycling, AC fan is not kicking on, Low side cycles between 45 psi and 0 psi, and high side is a constant 55 psi (all at 2000 RPM). There were a couple minutes in the drive home that the AC started blowing cold, but it was short. With the vehicle off, both sides are equalizing at 100 psi.

What's going on?

Cussboy on Sun April 15, 2012 8:54 AM

Find and fix your refrigerant leak. Just adding refrigerant is not the answer.

mk378 on Sun April 15, 2012 11:57 AM

The high side should never drop lower than static pressure. This suggests a sealer-related blockage.

JoJoDaClown on Sun April 15, 2012 1:59 PM

This is what I was thinking. I'm going to let it continue to cycle, and hope the clot clears.... I assume orifice tube would be the best place to start looking?

mk378 on Sun April 15, 2012 3:31 PM

If those pressures are real, the blockage would be somewhere between the compressor and the high side port. But you are using the gauge manifold properly, with the valve wheels on manifold closed to measure pressure, right?

Cussboy on Sun April 15, 2012 8:35 PM