Automotive Air Conditioning Information Forum (Archives)

vcsmike on Mon August 20, 2012 12:26 AM

Year: 2001
Make: Chevy
Model: Tahoe
Engine Size: 5.3
Refrigerant Type: R134a
Ambient Temp: 90
Pressure Low: 55
Pressure High: 215
Country of Origin: United States

As a result of the issues with the rear expansion valve noise & poor cooling in my newly refurbished A/C system (as detailed in this post: http://www.autoacforum.com/messageview.cfm?catid=2&threadid=23687&FTVAR_MSGDBTABLE=) , I opened it back up to at least replace the rear expansion valve. Based on the high low side number & the noise, my best guess was that I'd gotten a hold of a bad rear TXV. I ordered a new one from the dealership.

I have two concerns:

First, I pulled the o-tube to make sure it was clean, & I found a small amount of strange looking debris. It looked like very fine carpet fibers clumped together. There was not very much of it at all, & I could not find evidence of any more of it in any other part of the system. The system has been in use for a couple of months. Should I be concerned about this, or is a small amount of debris inevitable?

Second, I decided to drain the compressor oil to make sure it was clean. There was hardly any oil in the compressor at all. I use an old baby bottle that I keep clean to meausre A/C oil, & there was barely enough oil in the compressor to cover the bottom of the bottle. Should I be concerned that there was hardly any oil at all in the compressor? When I serviced the system the first time, I thoroughly flushed it, drained 2 oz of oil out of the new compressor, & distributed exactly 11 oz of PAG 46 throughout the system. Upon tearing down the system this time, I decided to also pull the condensor in order to hose it off thoroughly. Upon doing so, I found that my discharge hose had chafed against something & was leaking a little oil. It wasn't really bad. It was just a little moist with oil Is it possible that I lost enough of the system's oil through this hose to do damage? The system's performance has not changed since I first did the job. It's never been as good as it was back before the original compressor failed.

At this point, the two components in question for me are the compressor & the front evaporator. I'm replacing the rear evap & the condenser because either of those components could be clogged with debris that I wasn't able to get out when I flushed the system.

Should I throw in the towel on my new compressor, & assume that it's already damaged? Because this would presumably be damage due to debris or lack of lubrication, I assume there'd be no warranty despite the fact that I followed proper procedures.

Will the o-tube prevent too much debris from building up in the front evap, or will I have to replace it as well. I really don't want to replace it unless I absolutely have to. If it came down to a choice between pulling the dash or setting the car on fire, I'm undecided. :-)

Thanks in advance for any input.

-------------------------
Michael Keith
Vintage Car Solutions
Houston, TX

JJM on Sun August 26, 2012 4:50 PM

If the original compressor was damaged, the condenser should've been replaced. But since it wasn't partially cover the condenser to see if you can get the high side up to around 325-350 PSI. If you can, chances are the compressor is still good.

I am concerned, however, with those low side readings. Are you sure the OT installed properly, and the o-rings are sealing? Is that 55/215 reading at idle, or 1,500-2,000 RPM?

As for the oil, assuming you added the correct amount to a dry system, the oil is probably pooling in the evaporators, but since this is the discharge hose we're talking about - assume quite a bit of oil blew out.

I see no reason to replace either of the evaporators unless they're leaking. If they're flushed clean and don't leak, they should be good.

Joe

When considering your next auto A/C purchase, please consider the site that supports you: www.ACKits.com

vcsmike on Wed July 31, 2013 3:32 PM

Came here with another question, & I realized that I never posted a follow up to this issue. Through Rock Auto, I was able to talk with a Delphi technician (My new compressor is a Delphi). As it turns out, I had the system grossly over-oiled. The Delphi tech informed me that their new compressors ship with a full charge of oil & that the design is such that you can never drain all the oil out of it. Because I only drained 2 oz of oil from the compressor, I put that, plus an additional 9 oz of oil, in the system. The tech said that I should have only added 2 oz to account for the rear A/C.

As the compressor sat after running in the car for a month, he said that it had around 6 oz in it. Therefore, I flushed everything else, fitted my new rear TXV, rear evap, O-tube, & condenser. I also had the leaking hose repaired. I added 5 oz of oil to get to an estimated 11 oz total, vacuum, recharge, & all is well.

-------------------------
Michael Keith
Vintage Car Solutions
Houston, TX