Back in 2013, I was ready to try and get the air conditioning working in my car for the first time since I bought it in 2011. The car was set up with an R12 system, but there was no R12 left in my system as it had all leaked out. I decided to convert it to run R-134a instead of trying to get my hands on R12.
In order to convert it from R12 to R-134a, I had a few steps that I needed to go through. First, I had to replace the o-rings that are between the compressor and the hoses with R-134a compatible ones. I also had to convert the service port adapters, which I got from NAPA:
https://www.napaonline.com/p/TEM409902
https://www.napaonline.com/p/TEM409903
I removed the compressor and drained what little oil remained before filling it up with the correct amount of ester oil as well as some A/C florescent dye to help see any future leak. I then did a flush of the entire system using mineral spirits. I would fill up the high pressure hose with mineral spirits, put the end of the low pressure hose into a bucket, then push it all through with compressed air until it was all blown out, then repeated until the system appeared to be clean. It has been many years since I did all this, so some of the steps involved may be overlooked. But after flushing out the system, I hooked everything back up.
I purchased an A/C manifold gauge set, a vacuum pump, and I was ready to attempt my first recharge of R-134a. I pulled a vacuum on the system for the required time, then fired up the car, put the A/C on max and the fan on speed 4, then started to put in the R-134a. It was such a good feeling to hear the compressor kick on for the first time since owning the car. I filled it up with the proper number of cans, and enjoyed the A/C for the rest of the season.
At this point, it was September, and we also were expecting the birth of our first child that month, so we didn't drive it much at all the rest of the year. The following spring, the A/C was inoperable once again and I found that all of the R-134a had leaked out. From then until now, I hadn't made the A/C a priority as our family continued to grow over the years (we now have four kids) and the car just didn't get much attention.
Fast forward to 2021 and I decided that if I was going to enjoy the car again, I absolutely had to have functioning A/C. I got out all my A/C tools and started seeing if I could figure this system out. I checked all the lines and fittings to see if I could see any dye anywhere, even though it had all leaked out 8 years prior, but I found no evidence of it anywhere. I dove right in after that and pulled a vacuum on the system. I wouldn't hold a vacuum very long, so I decided to fill up the system using my air compressor to see if I could detect a leak somewhere.
Sure enough, when I filled up the system, I could hear a hissing sound that seemed to originate from the compressor itself. There is a seal in the compressor that commonly goes bad, which I believe is the shaft seal, and I felt it was better for me to get a new compressor rather than rebuild the 40 year old original. I bought a Sanden 4708 Compressor from Auto Air Online for $239 (part # 05-4708) and it arrived within a few days. Excellent service.
The new compressor came filled with oil, so hypothetically, all I should have had to do was remove the old compressor and install the new one, pull a vacuum, then fill it with R134a, right? That's what I did, but I can't get the car to get colder than about 60 degrees Fahrenheit out of the vents on a 90 degree day. My other cars blow air closer to 40 degrees F, so something is still not quite right.
Talking with my friend that's a mechanic, he thinks that if the hoses are holding pressure, which I don't know if they are, there could be a blockage somewhere in the system, possibly something caught in the orifice tube, or somewhere else. I have much more work to do on this topic as I need to see if the system continues to hold pressure or not. If it does, that likely means that replacing the compressor solved the leak. If it doesn't, hopefully I can find where it's leaking out. I did add some more A/C dye to the compressor before I installed it, just in case there is a leak that I need to track down.
Until that happens, here's picture of the shiny new compressor. Hopefully I can get this system working better by the end of the hot season. I have a new orifice tube and dryer (accumulator), in case I dive into this further this year.
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