therewolf

At the heart of the matter, you've been throwing parts at the system.

If, at this point, you still haven't found the problem,(and there have been many great suggestions and answers besides mine) you may need to find a specialist, and leave the problem to him. Rather than saying "replace this", be sure the tech knows the repair history, and your repair OBJECTIVE, which is "ice cold A/C".

There's no reason your truck should be the exception to the rule.

sbgalaxie

I was hoping to find a silver bullet here. My '96 C3500 Crew Cab has never had really cold a/c. The Chevrolet dealership where I bought it checked it out several times under warranty and found nothing. I've changed compressors using accepted procedures with new receiver and orifice tube. I've changed the evaporator core because a detector indicated a leak - big job an no leak. The system simply will not, nor has it ever been able to keep up with heat load on high-90 degree days. Low 90s or less, and all is well with 40 degree air. On hotter days, it will be as high as 60 degrees output. I've had it to an independent A/C shop, and they say it performs as designed. Now, I know cold air. Our 2002 Tahoe would hurt you in a few minutes, as would several other vehicles we've had. The C3500 has just always been marginal in the A/C department.

I was hoping that there might an endemic problem with these early 134a systems that could be remedied with a larger condenser or something. I'd appreciate any thoughts.

sbgalaxie

Good morning, and thanks for the input. Here's a little more history....as I had mentioned, the experts had left me disappointed, saying the performance is as it should be. Regarding throwing parts at the truck, I'm not arrogant enough to say I'm an expert, but I'm well enough versed to repair just about anything short of an automatic transmission. The original Delphi compressor was leaking badly. It had been changed under warranty before. The Sanden conversions are popular due to the leaking, so I went that route and was quite satisfied. I changed the evaporator core out of ignorance. First, I used an unreliable tester. Further I didn't realize that the orifice tube was near the condenser rather than at the evaporator, and the fitting at the evaporator galled when I tried to remove it. I've never had a catastrophic component failure, and the orifice tube wasn't dirty when I changed the compressor. I used an venturi vacuum pump, I did "dump" the refrigerant, I did introduce it in liquid phase. I always run on Max to try to take advantage of cool return air. Since theser repairs, I have had an expert A/C shop check it out, and was told it's fine, but it's very obvious to me it's not. The thing can sit in a parking lot idling next to another vehicle that's making tons of condensate and hardly make a drop. The drain isn't plugged either. I'm not going it completely alone as I have good, experienced folks to call on for advice, and they are as stumped as me. It's a very rare thing for me to have service work done on any of my equipment just because it's a frugality thing, and I so often see service folks today who can only change parts based on computer diagnostics. It's very hot and humid here, and my oil cooler is in front of the condenser. At the risk of throwing more parts at the problem, I'm considering trying a condenser on the off chance that it has a restriction that's always been there. Or, maybe I should just bleed the system, check the orifice tube again and recharge.

Thanks again. I really appreciate the input.

samger2

Well, all the parts I put on the truck needed to be replaced. The initial reason I started looking into this was because it simply wouldn't blow anything remotely cool...warm air came out when I turned on the A/C. I have some good friends in the auto industry, so one of the guys did an evac and then put 2lbs of R-134a back in the system. This worked for all of about 10 or 20 minutes...then blowing warm again. They put dye in the system and you could see a pretty hefty leak at the compressor. I also had it into the dealer for an unrelated problem and while they were looking at it they checked the a/c issue and verified for me that the compressor needed replaced. So I replaced it. Took it into my buddy, he did another evac, then recharged the system again...blew cold for a while...then I heard a hissing noise and looked up front and the condenser was blatantly leaking and hissing dripping onto the parking lot. Next was a condenser...did that, and while I was at it replaced the lower line going into the condenser because it ripped when I was trying to remove it from the old one. Put everything back together and again had an evac and recharge done. Blew "cool" but not cold...did some thinking and realized I never put an orifice tube in when I replaced the condenser and lower line...so got an orifice tube, put it in, another evac and recharge...and it helped significantly.

And here we are...blows colder than before, but certainly not "ice cold"

therewolf

Try the yellow pages in your area specifically for an A/C specialist. DON'T GO TO A DEALER. For something like this the dealer is more worried about being held accountable under warranty than really fixing anything. In most large cities there should be a specialist or two which deals solely with A/C.

If all else fails, take a road trip to San Diego, California, Houston ,Texas, or Miami,Florida. They know how to fix air conditioning down there.

samger2

Yeah...I think I will do just that...look for an a/c specialist...otherwise, as you said before I'll just be throwing parts at it.

Thanks for all the suggestions gang!

samger2

well...got in the truck yesterday to come home and it's blowing completely warm now...not even a hint of cool. Didn't get a chance to look over anything to see if I could notice any leaks...my buddy wants to take one more look at it before I go to a specialist. I have nothing to lose because he'll look at it and recharge it for free. About the only thing I didn't replace was the upper line to the condenser and the accumulator...so who knows.