jhdeval
Well-Known Member
Is there a set guide to how much R134 is needed or how do I calculate how much I need?
How much R134?
- Thread starter jhdeval
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67Dart273
Well-Known Member
"It depends". I've seen percentage recommendations of percent of R134 of the original R12, IF you have that information, but that only applies if the sytem is "dead stock."
If you've added a larger condenser, larger/ longer hoses, larger drier, etc, the amount no longer applies.
That's why I always charge by pressure/ temerature and SUPERHEAT at the compressor, about 15-20*F.
If you've added a larger condenser, larger/ longer hoses, larger drier, etc, the amount no longer applies.
That's why I always charge by pressure/ temerature and SUPERHEAT at the compressor, about 15-20*F.
fenderman33
Well-Known Member
A good starting point is filling it up until the low side pressure it at ambient temp.
-Jon
**edit: That's when the car is off, not with the compressor running**
-Jon
**edit: That's when the car is off, not with the compressor running**
BillGrissom
Well-Known Member
The recharge bottle (19 oz I recall) I got at Autozone had a pressure gage and a chart showing the typical low side pressure at different ambient temperatures. A rough rule is ~50 psi with compressor running if ambient temp is 75 F.
If it is a stock system put 75-80 percent of what the R12 called for...
jhdeval
Well-Known Member
It is a custom system. I found online 25-44 PSI on the low side is within normal range. Does that sound right? BillGrissom is saying 50psi. I have 3 12oz cans right now.
BillGrissom
Well-Known Member
I was going from memory and the rather inaccurate gage on the recharge bottle. I recharged the R-134A in my 96 Voyager last June since the AC wasn't cool enough. I recall reading ~25 psi low side (AC clutch on). After adding the full can (19 oz I recall), it read ~50 psi and the AC now works great. I didn't get all 19 oz in since the plastic valve on the kit had a crack and some leaked. In your case, I would add a 12 oz can. If it helps, but not enough add another can. But don't go over 50 psi low side.
Good to also monitor high-side pressure, but requires another gage. You can get an AC kit at Harbor Freight w/ multi gages and valves. I have one (~$25 on sale), but didn't even bother to use it that time.
Good to also monitor high-side pressure, but requires another gage. You can get an AC kit at Harbor Freight w/ multi gages and valves. I have one (~$25 on sale), but didn't even bother to use it that time.
jhdeval
Well-Known Member
I borrowed a set of gauges. Unfortunately last night I was going through my hose connections and it turns out I am missing the large side of my condenser and both sides of the compressor. Sucks I was hoping to be driving cold tomorrow.
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