AC leak; can't find it

[VIKING_MECHANIC]

So over the last month or so I've noticed my AC has been underperforming(97 C1500, 5.7). It would take a good 30-45 minutes of driving around before the interior temp would drop to 60(MAX temp it's dropped to is 58 with my condenser fan ON). So I connected R2D2 to it about two weeks go and the pressures seem normal for the outside temp and humidity at the time(95 degrees and 60(?) humidity). Low was 40 and High was 225. So I evacuated the system and it had 1.7 I believe at the time. I also checked for leaks with a UV light, but didn't find anything.

I recharged it and went about my day. Two weeks later(today), I noticed the same issue. So I put R2D2 back on the truck and the pressures were about the same for the given temp and humidity. (100 and 60-70 humidity). And this time it recovered 1.8Lbs. So I have a leak somewhere.

Here's the thing, I've checked all lines, connections, evap/condenser/receiver for leaks and can not find any green dye anywhere. I suspect the condenser but I do not see any dye or major damage to it.

I don't know a huge amount about AC systems, so what is you guys thoughts?

 

[1998_K1500_Sub]

I've checked all lines, connections, evap/condenser/receiver for leaks

Have you checked the compressor?

The HT6 is notorious for leaking at the middle seam.

Check the bottom of the compressor for oil / dye and report your findings.

 

[grampadirt]

I do this....after doing any repairs and before I pull a vacuum on it I pressurize the system(100psi maybe)and go around the entire system with a squirt bottle with water and dish soap in it.I have found a few leaks looking for bubbles this way.

 

[bigshane]

I've checked all lines, connections, evap/condenser/receiver for leaks and can not find any green dye anywhere. I suspect the condenser but I do not see any dye or major damage to it.

Did you remember to check the evaporator drainage for dye? (dripping onto the ground, under the passenger side floorboard, after running awhile)

 

[VIKING_MECHANIC]

So I was able to find the (small) leak after reading what @1998_K1500_Sub posted. It was on the bottom of the compressor, both in front and rear, but very hard to see even with UV light.

So replaced the compressor, applied vacuum which held for about 20 minutes, so I went ahead and charged the system. Annnnd the clutch on the new compressor would not engage. WTF!!!!!

I check all my connections and still did not engage. So I checked the power and ground to my HP switch (had both) and the clutch switch which had ground but not 12v...

The issue ended up being the pinouts on the relay center for the AC relay, the pins were flatted out so they were not "grabbing" onto the relay. Took a few minutes to correct that and now it works.

The AC still doesn't really drop much below 60(max i saw was 58), but thanks to what @GoToGuy posted in another topic about better AC, I understand better about the systems limits, at least in stock setting. After Reading that post, I got some ideas to increase my AC's performance especially before I move back to Texas lol.

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[1998_K1500_Sub]

There's lots of discussion in this current thread about AC, engine cooling, air leaks, blower fans and related topics. Read through it, it gets interesting.

Better AC with different size pulley?

With the recent heat wave, the AC once again leaves a lot to desired once idling in the torturous midday sun. Had my AC guy check the refrigerant, pressures, airflow, etc. All was good. The AC is great if it’s below 90 outside. Once it gets over 90 it starts struggling at idle. I can elevate...

www.gmt400.com

 

[scott2093]

Had to look up that Robinaire unit...nice....
Better than the snake pit....

 

[VIKING_MECHANIC]

There's lots of discussion in this current thread about AC, engine cooling, air leaks, blower fans and related topics. Read through it, it gets interesting.

Better AC with different size pulley?

With the recent heat wave, the AC once again leaves a lot to desired once idling in the torturous midday sun. Had my AC guy check the refrigerant, pressures, airflow, etc. All was good. The AC is great if it’s below 90 outside. Once it gets over 90 it starts struggling at idle. I can elevate...

www.gmt400.com

That was the thread I was referring too, but I forgot to link it.

My short term solution maybe to replace the fan clutch with a serve duty one and maybe a fan with more blades.

 

[VIKING_MECHANIC]

Had to look up that Robinaire unit...nice....
Better than the snake pit....

It's the machine we use at my work.

Not sure I get the snake pit reference?

 

[scott2093]

Not sure I get the snake pit reference?

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