Started buying new AC parts. Everything will be new and clean. How many of the short or tall Freon cans of 134 do I need to grab?
How many cans of freon for new system?
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Freon is the Dupont name for R12. The amount needed is based on weight/high and low side operating pressure according to temperature. I have a chart somewhere around my house with the information on it but I'm not sure where it is. I do know you need less r134a than r12. Many cans of r134a come with a simple gauge that tells you when the system is full. You should be able to do a google search for r12 to r134a conversion and find the information that way.
A couple things you need to do for a good working system. When you buy new parts they will always come with ends capped. Keep them capped, when you install them keep any openings capped. Moisture can collect inside the piping or parts and will damage your system. Next, your compressor will require oil, somewhere around 6oz, plus or minus. It needs to be correctly added to the compressor. You should take it to a shop or rent a vacuum pump and gauges. The system needs to have a vacuum before adding R134a because air does not compress and/or remove heat. The amount needed depends on the total size of the system.
Biggest waste of money on the whole car I ever spent was the a/c. Consider saving big money instead. Delete it and go for the shorter belt drive. I think I'm going to delete mine and the $60 charge ( 2 cans - theyd be $70 at least now) wasn't worth it either. Of course I was in New Mexico part of the time which is about as extreme as you can ask of an a/c. Huge waste of 100s of dollars. Does it work at all: not over 90 degrees and thats when I need it to work. Luckily my car is white. $450 I could have gave to a charity instead. Yes I tested for leaks several times it was perfect.
If you are going with R134 you need to start researching this. Good to have all new parts, that way you can begin with fresh R134 and it's correct type of oil. Best if you can find a compressor for your car that is designed for R134. I bought a digital postal scale on Epay for like $20 and I add only the correct amount of freon. Your car came with a spec for how many pounds/ounces of R12. The correct amount of R134 will be different because they are different gasses. Pro's know how to adjust the amounts for equivalent cooling and that info can be found on the net. Read up on this at the HVAC sites, "how to convert R12 to R134". The method of adding freon slowly and watching a thermometer jammed in a duct works, but is crude and you can overcharge the system causing damage. The reason the system needs to be vacuumed down with a good pump is: 1- to test for leaks. If it holds 29" vacuum for an hour with the pump off, probably no leaks. 2- water boils at 29" vacuum so you are boiling any moisture out of the system before adding the R134. Hoses are different too- R134 may leak through old style hoses. R134 hoses have a teflon liner. My AC leaked badly but I felt all this was too much trouble so I just acquired a used rebuilt compressor, new accumulator, and new orifice for my wagon and filled it with an R12 substitute called ES12. I was able to keep the same mineral oil and fill specs and it works great.
I believe g bodys a/c units take 52 ounces of the old stuff and IIRC 80% is rule of thumb for the conversion to r134.
Typical g body with the R4 compressor specs 3.25 pounds of R12 (A6 compressor system 3.5#). I usually figure about 85% of that for R134a.
As was said, best to have it evacuated/recharged by somebody that knows what they're doing.
The biggest gripe with most old A/C systems is that the ducting leaks everywhere. I did my old 80 Malibu with R134a, and pulled/cleaned/resealed all the ductwork while I had the dash out. Make sure the evap case and core are clean as well. Cooled very well even in Oklahoma summers near 100 degrees and high humidity. The only gripe I had with that system was that the blower didn't blow very hard at idle. At speed, it cooled well enough that the wife said it was too cold in the car....and she is NEVER cold.
As a side note, R134a is in the process of being phased out by the OEs. Have run into late model Chrysler stuff with R1234yf...which currently is about $125/pound.
As was said, best to have it evacuated/recharged by somebody that knows what they're doing.
The biggest gripe with most old A/C systems is that the ducting leaks everywhere. I did my old 80 Malibu with R134a, and pulled/cleaned/resealed all the ductwork while I had the dash out. Make sure the evap case and core are clean as well. Cooled very well even in Oklahoma summers near 100 degrees and high humidity. The only gripe I had with that system was that the blower didn't blow very hard at idle. At speed, it cooled well enough that the wife said it was too cold in the car....and she is NEVER cold.
As a side note, R134a is in the process of being phased out by the OEs. Have run into late model Chrysler stuff with R1234yf...which currently is about $125/pound.
Why not just order R12 from Mexico and put it on one of those cheap prepaid cards from walgreen's if your scared p*ssies. Converting my a/c to 134 was one of the top few biggest mistakes I made on my car. It felt like a refrigerator inside before I wasted hundreds of dollars sabotaging it with crap 134a.
edit* I am j/k but all jokes aside ignore my tirade; When I converted to 134 it was at the request of my fiance`. Personally, I wanted to spring for some Bilstein shocks instead. Now I'm not in the relationship anymore but money is tighter for me than it was at the time. The charge lasted only 1 season. The a/c 'works' but when I got into a newer car like my Silverado or Cadillac it's clear that no matter what I do the a/c was never going to be as good as a newer car in comparison. A short trip in my grandpas old SL600 woke up to what a waste of money I had spent on this endeavor. The a/c could barely do 85% of what a modern unit can do. Plenty of 90 degree days I found myself w the windows open fan full blast. The a/c just couldnt keep up. Never again!
edit* I am j/k but all jokes aside ignore my tirade; When I converted to 134 it was at the request of my fiance`. Personally, I wanted to spring for some Bilstein shocks instead. Now I'm not in the relationship anymore but money is tighter for me than it was at the time. The charge lasted only 1 season. The a/c 'works' but when I got into a newer car like my Silverado or Cadillac it's clear that no matter what I do the a/c was never going to be as good as a newer car in comparison. A short trip in my grandpas old SL600 woke up to what a waste of money I had spent on this endeavor. The a/c could barely do 85% of what a modern unit can do. Plenty of 90 degree days I found myself w the windows open fan full blast. The a/c just couldnt keep up. Never again!
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