Model: Sierra 3500
Engine Size: 6.0
Refrigerant Type: R134a
Ambient Temp: ~90
Pressure Low: 0
Pressure High: 0
I went to replace my comp and accumulator (and orrifice tube) for the third time now. All were operator errors except the first time, which I have no idea why my compressor locked up. Over the last few days I have replaced the compressor, accumulator, orrifice tube, and added a inline filter that was $50. I then bought a harbor freight vacuum pump and mani guages.
My question is this- I pulled a vacuum and it went down to 30 very quick and left it for an hour. It lost vacuum in 5 mins. I have 6 cans of r134a and a robin air leak detector. Should I pull vacuum and switch hoses as fast as I can to get r134 into the system so I can sniff out the leak, or, just put the r134 in without vacuum? I'm new to this but have read a lot on these forums. Any help is greatly appreciated.
Well, like I said it vacuums to 30 and it stays at 30 until I turn the pump off. Then it drops steadily over 5 or 6 mins till its back at zero. So there's no way I can check the leak with r134 and a electronic leak detector? I don't have compressed nitrogen. Just compressed air, and its by no means dry.
I've checked the pump and guages now, and its def not them. I hate that I just spent all this money on the vacuum and guages and am still having to go pay $100 plus to have it done.
For a leak that large, start at zero psig (full of air), put in R-134a up to 10 or 20 psi, and start checking with electronic leak detector.
Edited: Mon June 25, 2012 at 5:52 PM by mk378
I found it! The cycle switch on the accumulator had cracked down the treads. $20 and its holding good now. Knock on wood. I just hooked a can of r134 up and barely let any in and heard it hissing right away. I know that may be bad but I just let a little gas in. The switch is 4 inches away from the port. Hopefully it won't do any harm. Thanks guys for your replies. I have another project I'm starting next week so I may need some help then! Thanks again.
Yeah I knew better than that. I think he just said r22 meaning refrigerant.. But I know enough to not add anything other than r134a to a r134a system.
I would also suggest that after 3 blown compressors, your condenser is going to be clogged up with metal debris.
Yeah I think I still have a problem. I charged it and it went to 40psi with just 1.5 12oz cans of r134a. It blew cold. Now I think I made a big boo boo. I put a inline filter on the system. It said to put it on the low side. I just realized that its just before the high side port! I had the lines off the truck and on a 2004 GMC sierra 3500, the high side is just a few inches from the low side port, orrifice tube and expansion valve between them. When I charged it, the pressure on the high side was at 280 but now has dropped to about 225. I'm going to have to recover, and replace the line now right?
I take that back. I got the instructions out for the inline filter, and it says to mount it before the orrifice tube. That just so happens to be just before the high side port. Did I mess this up?
Also, ambient temp is about 95 right now, so where should my readings be on high and low side.
I feel like there's a lot of pressure built up behind the quick coupler on the high side. Kinda scared to remove it.
I'm an idiot . I was reading the inner ring on the guage, I should be reading the outer ring right? Wow. The outer ring (says r134a on it) says +6 low side, +58 high side. So I'm just now starting to get it charged, right?
I was supposed to have a HVAC buddy of mine over here that's done this a lot, but he couldn't make it till next week so I tackled this myself. Should have waited I guess.
Read very outer scale, the one that is psi. When working on a stock system with a specified charge amount, always install that charge then evaluate performance.
R22 won't penetrate barrier hoses.
I've saved hundreds on service by spending thousands on tools.
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