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I was able to charge the car this evening after convincing my daughter to drive the Honda minivan.
I first pulled vacuum on the system for ~10min.
I then turned off the pump and closed both valves. The car then sat for 30min and I came back to ensure the vacuum level had not moved. Happy to report the gauge was still at the same spot. I then turned on the vacuum pump again and vacuumed the system for 45min.
Next step was to put in the R134a. R12 system requires 37oz so I set a target of 1.7lbs (27.75oz) or 75% of the R12 freon weight. Based on my reading I have seen proposed ranges between 70-80% of R12 freon weight. I ended up putting in two 12oz cans and about 1-2 oz of the final can as it didn't seem to want more freon. In total I put not more than 26oz R134a in the system and will wait for it to warm up to use the gauges to determine if the system is fully charged.
Quick question, do you keep the low pressure side R134a adapter on the fitting or do you only install it when servicing the ac? I am concerned the adapter will be a potential leak point over time.
Thank you, thank you! I need to do this to my car while it is all apart. Is there (does there need to be?) an upgraded evaporator core, and if so, where would I find one?
Thank you, thank you! I need to do this to my car while it is all apart. Is there (does there need to be?) an upgraded evaporator core, and if so, where would I find one?
I think you are referring to the condenser. The AC will have a set efficiency so the answer likely depends upon the climate in which you live. For Charlotte, NC it was not an issue last summer and the AC felt cold, but perhaps if you live in Houston you will want the increased efficiency. If you review the earlier part of the post there were two links to upgraded condensers.
BTW, the Harbor Freight pump worked like a champ. It was very quite, did not smoke, nor did it leak any oil.
Nope, meant evaporator core, I read what you wrote on the upgraded condenser core and it is what prompted the question. Phoenix has 60 plus days per year of 105+ degree temperatures and in the past my car was miserable to drive if there was any heat soak from being parked inn the sun. The system just couldn't catch up. I know the evaporator cores for other cars I have changed out appear more efficient and was hoping in the 30 plus years since the original was installed there was a more modern (designed for R134a) evaporator out there. I have a complete spare evaporator box that I intend to take apart, I will see if I can have an upgraded evaporator core made.
I really do appreciate all your work on this very informative thread. If I am able to do something like that, with your permission, I would add it here.
Nope, meant evaporator core, I read what you wrote on the upgraded condenser core and it is what prompted the question. Phoenix has 60 plus days per year of 105+ degree temperatures and in the past my car was miserable to drive if there was any heat soak from being parked inn the sun. The system just couldn't catch up. I know the evaporator cores for other cars I have changed out appear more efficient and was hoping in the 30 plus years since the original was installed there was a more modern (designed for R134a) evaporator out there. I have a complete spare evaporator box that I intend to take apart, I will see if I can have an upgraded evaporator core made.
I really do appreciate all your work on this very informative thread. If I am able to do something like that, with your permission, I would add it here.
Anything that benefits the knowledge of the forum should be posted so don't need my permission to update this thread. I played golf in Phoenix back in 2008 when temps were ~113F and I had heat exhaustion after about 9 holes and had to ride it out with a wet towel wrapped around my head.
From memory I saw that someone had replaced the evaporator with a new unit that was almost identical to stock, but required some slight mods to make it fit. Not sure if that evaporator was better from an efficiency standpoint so I'm curious to see what you find.
The evaporator is fine for the size of the car, the real issue is that the condenser cannot get heat out of the refrigerant fast enough and the system becomes heat soaked.
The main swap you need to worry about is swapping the expansion valve to the r134 one from the r12 one. This is what controls the pressures on the high and low sides.
They're like $25 and worth the effort to swap as your old one is likely corroded inside, plus they are a mechanical part and do fail.
A way to combat heat soak in any car is to drive a few minutes with the windows down and AC on low fan. This allows air that is hotter than ambient to get out of the car and allow the evaporator to get as cold as possible.
Close the windows and crank up the AC and you will cool any car as fast as possible.
I am no expert but aren't you suppose to add oil, either Esther or PAG Oil to properly oil the compressor?
Use PAG only if your system is new and has no residue from past R12 in the system. Even less than 2% of mineral oil left in the system can cause PAG to gum up and destroy the system.
Use ester oil if you are converting from R12 and reusing most of the components. It wont react with leftover mineral oil.
03-07-2018, 09:34 PM
