Confusing A/C Work & The New Problem

[Elemino]

So today My dad and I tackled the A/C not working. This has got to be the strangest acting system I've ever seen. The compressor runs continuously until you put a certain amount of gas in it??? It then starts to cycle the compressor. Then we got the charge to a point where the system eventually was putting out 42 degree air. Pretty nice, but I'm not sure if that's where it should be at max A/C (ambient temp of 76). The low side varied between 25 to 30 while the pump was running, but the high side never went over 150psi...? My Navigator runs in the 200's on the high side. Such a confusing system!

In the end, I determined the problem is there is a leak. One of the hoses running from the condenser to the compressor was covered with green dye. I believe the hose is leaking. It would appear other than that everything is fine.

While down there I spotted something that concerned me. There's a structural brace missing from the driver side. It was either damaged and broken off, or someone cut it out. It attaches directly behind the the front wheels, and attaches to the body near the cat converters. I hope the body isn't being damaged in some kind of way while this part is missing, but it is definitely at the top of my list now!

Everytime I fix something, I find a new problem!!!

 

[joegr]

Well, I'm glad you used low and high side gauges, but you really should have looked up the pressure/temperature chart for the LS AC.

At 75F, 120 to 170 PSI is normal for the high side, 30 to 50 PSI is normal for the low side.

It's a variable displacement/capacity scroll compressor with a thermal expansion valve at the evaporator. Note also that it has no low side pressure switch of sensor. It has a high side pressure sensor. At start up, if there is no high side pressure, it won't start. While running, if the high side goes too high, it will cycle. Under normal summer conditions, it does not cycle. In cool weather, it will.
(Low evaporator temperature (there is a sensor for that) will also cause it to cycle.)

 

[oddball]

Remember that you shouldn't charge 134 systems depending on pressure. Charge to the manufacturer's spec by weight and ensure pressures don't go too high.
The high side does not get very high on this car. It's been over a year since I last mucked with mine, but I don't think the high side got over 200.
The weather was really nice this weekend, and not too humid, so it should have gotten below 40.

 

[Elemino]

I ran out of gas to put in it, there was no way I would have been able to over charge it. The system wasn't completely empty. I would have had to evacuate the system to know exactly how much I needed to put in. I was basing those pressures off a chart from a A/C repair book. I pretty much ignored the high pressure side. I was watching to see it was going too high, but it barely did anything. What I was more concerned about was the low pressure side, and it was pretty close to what it should have been. Either way, it will have to be redone, because of the leak.