How much r134a

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MCH86GN

Well-Known Member
Joined
Aug 20, 2008
Messages
1,478
I need to know approximately how much r134a is needed to charge my AC or what the pressures should be for high and low side for a given ambient temperature? Luckily I have a set of gauges. I don't want to overcharge and I have put about 24oz in and I can't to locate how much r134a is needed or a temperature vs pressure. At idle with the fan running on high it's not really blowing all that cool.

Thanks,
Charles
 
I need to know approximately how much r134a is needed to charge my AC or what the pressures should be for high and low side for a given ambient temperature? Luckily I have a set of gauges. I don't want to overcharge and I have put about 24oz in and I can't to locate how much r134a is needed or a temperature vs pressure. At idle with the fan running on high it's not really blowing all that cool.

Thanks,
Charles

Hi Charles,
I read your AC Refrigerant Line and lessons learned thread and that is some unfortunate story, but I have to ask you did you vacuum the system since you replaced the AC lines?
Here is a AC Temperature Pressure Chart, I hope this will help you out:
 

Attachments

Hi Charles,
I read your AC Refrigerant Line and lessons learned thread and that is some unfortunate story, but I have to ask you did you vacuum the system since you replaced the AC lines?
Here is a AC Temperature Pressure Chart, I hope this will help you out:


Yes , I bought the vacuum and gauges from Harbor Freight. I had to do my s10 and Explorer. I had my s10 in a local shop and they must have broken the seal on my s10's AC system. I got it back the AC didn't work, nor did the oil sending unit. What is funny is that called the guy at the shop and asked if I needed to evacuate the AC system before I recharged and he nope. Since it as fall of last year, I waited until this summer. However, I'm surprised that a shop would tell you not to evacuate a system that has gotten air and/or moisture into. In theory they should have evacuated it and recharged it, but they didn't. I have not had good luck when it comes to local shops in my neighorhood and that distrust has pushed to do things for myself and hands on the best way. I had to replace my heater core in my s10. It took a long time to get the dash off to do it, but the dealership estimated it at $600. Now I know how to pull that dash off with ease. Not to get too far off the point.

I vacuumed it down for about 10 minutes, let it set and made sure there were no leaks and then did it for 30-40 mins. Let it set over night and checked again to make sure that the gauge pressure was unmoved. Like I said I have only put about 24oz of r134a in it. I'm just concerned now because of how hot the high side port is getting. It got so hot one time it melted the plastic cap to the adaptor. However, the AC had been on for 5 or 10 minutes, long enough to kick the the fan on from the temperature switch. That is when I learned what the little jumper harness was for. I couldn't figure it out and didn't know what it was for. So as I was helping my father in law take his fan out he told me that at a light or when he was setting the car would blow warm air and that the fan wasn't coming on. So we fixed his and then it just clicked, hey that is what this jumper is for. So I can connect switch the fan on/off if the AC is on and the engine coolant temp wasn't high enough to kick the fan on. I connected it up and there is a switch under the dash and it is a two speed fan, with an off position. Needless to say I will probably run it high when crusining. The fan did make some different in the vent temperature, but not what I would call cold.

Thanks for the attachment.
 
Hi Charles,
I read your AC Refrigerant Line and lessons learned thread and that is some unfortunate story, but I have to ask you did you vacuum the system since you replaced the AC lines?
Here is a AC Temperature Pressure Chart, I hope this will help you out:

I also found this link. Sounds like the gauges are your best friend here. You have to monitor the amount your putting in with regard to your gauge pressures. It also sounds like a lot of people put the refrigerant when the weather is a little cooler. I was doing it last night, oh my was muggy and warm out. Anyway, I figured I would post the link to gnttype.org

http://www.gnttype.org/techarea/airconditioning/r134pics/r12-2-r134a_conversion.html
 
I also found this link. Sounds like the gauges are your best friend here. You have to monitor the amount your putting in with regard to your gauge pressures. It also sounds like a lot of people put the refrigerant when the weather is a little cooler. I was doing it last night, oh my was muggy and warm out. Anyway, I figured I would post the link to gnttype.org

http://www.gnttype.org/techarea/airconditioning/r134pics/r12-2-r134a_conversion.html
Thanks that look like a good info
By the way, I saw this in one of the speed show, and Walmart has them cheaper then others. It also has a gauge letting you know how much to put into your system.
http://www.walmart.com/ip/AC-Pro-Professional-Formula-Refrigerant/20461354
 
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