Freon Question
#2
Join Date: Nov 2007
Location: Eastern PA,
Posts: 10,462
There is no time limit I am aware of on Freon. I was a trained AC service tech.
I have seen 50+ year refrigerator still running there orginal charges
I have seen 50+ year refrigerator still running there orginal charges
#5
Hope you don't mind me high jacking this thread...
Anybody know how much freon & oil a 3.8 '97 Firebird should hold? I've collected all the tools and am getting ready to try my hand at my first A/C job.
Also, I've read that the system should be under vacuum for 30+ minutes. Does that sound right to you guys?
And...are there any prone problems with the A/C systems on these cars? I can not find an obvious leak via using the dye. I'm going to replace the orfice, dryer, all o-rings, and schrader valves. If it doesn't hold a vacuum, then I don't really know where else to look. Any quirks on these cars?
Compressor/clutch still good. Last summer I was able to limp it along by charging it twice. Each time it took just a little freon, not much. This summer it won't last more then a day or so. Hoping it is just a bad o-ring or schrader valve.
Anybody know how much freon & oil a 3.8 '97 Firebird should hold? I've collected all the tools and am getting ready to try my hand at my first A/C job.
Also, I've read that the system should be under vacuum for 30+ minutes. Does that sound right to you guys?
And...are there any prone problems with the A/C systems on these cars? I can not find an obvious leak via using the dye. I'm going to replace the orfice, dryer, all o-rings, and schrader valves. If it doesn't hold a vacuum, then I don't really know where else to look. Any quirks on these cars?
Compressor/clutch still good. Last summer I was able to limp it along by charging it twice. Each time it took just a little freon, not much. This summer it won't last more then a day or so. Hoping it is just a bad o-ring or schrader valve.
#6
Cant tell you how much Freon you need sorry.
yes the system should be evacuated for a couple of reasons. First to remove any humidity that has collected in the system that can cause water ice that will restrict flow and lower AC performance. second only freon and oil are supposed to be in the system for it to function correctly, air in the system can cause ice and limit the ability of the freon to chill as it expands.
To charge the system properly you need to monitor both the high and low side as you add freon to the system. You can quickly overcharge the system if you dont do this as there can be an inblanance from time to time as the system equalizes.
Just to me safe replace all the seals and both the schrader valves before recharging the system again. If not you are just throwing money away and we all know that is not good. Oh and around here most AC shops will recharge the system for about $50-$75 and that includes the evacuation and oil. To leak test it takes longer and will cost you more.
Massey
yes the system should be evacuated for a couple of reasons. First to remove any humidity that has collected in the system that can cause water ice that will restrict flow and lower AC performance. second only freon and oil are supposed to be in the system for it to function correctly, air in the system can cause ice and limit the ability of the freon to chill as it expands.
To charge the system properly you need to monitor both the high and low side as you add freon to the system. You can quickly overcharge the system if you dont do this as there can be an inblanance from time to time as the system equalizes.
Just to me safe replace all the seals and both the schrader valves before recharging the system again. If not you are just throwing money away and we all know that is not good. Oh and around here most AC shops will recharge the system for about $50-$75 and that includes the evacuation and oil. To leak test it takes longer and will cost you more.
Massey
#7
Join Date: Nov 2007
Location: Eastern PA,
Posts: 10,462
If your system has not had a major blow out you should not have to put oil in it. You really need to track down the leak and not just throw parts at. A "one day leak" should be very easy to find. You may need to step up to a leak detector. If you are not seeing any dye and your checking everything you could have an issue with your evaporator.
Do not install the Dryer receiver untill you figure out your problem. The life of the dryer is based on how my time the system has been opened not time.
If you find a leak say at the bottom of the condensor you may want to add some oil but if the compressor has not been removed and emptied do not put in the entire systems requirement of oil.
Do not install the Dryer receiver untill you figure out your problem. The life of the dryer is based on how my time the system has been opened not time.
If you find a leak say at the bottom of the condensor you may want to add some oil but if the compressor has not been removed and emptied do not put in the entire systems requirement of oil.
#8
Good point about not needing to add all the oil unless the compressor is replaced and the lines are flushed. Here's an idea: measure the amount of oil that is in the old accumulator, and add back that much oil.
To help aid in finding the leak, would it be possible to pressurize the system with an air compressor and then use soap and water? The high side should be under a lot of pressure, and the low side should be pressurized too, but if it looses what freon I've added in a day or so would the system still be holding pressure at all?
My biggest fear is that the evaporator is leaking. If I have to remove it, how big of a job is it on these cars?
Thus far I have picked up a vacuum pump and a good quality A/C manifold set. I don't see a reason to flush the lines on this job, but I'm going to pickup an A/C flush can next as I need to replace the compressor on my K3500. That will be my second A/C job.
To help aid in finding the leak, would it be possible to pressurize the system with an air compressor and then use soap and water? The high side should be under a lot of pressure, and the low side should be pressurized too, but if it looses what freon I've added in a day or so would the system still be holding pressure at all?
My biggest fear is that the evaporator is leaking. If I have to remove it, how big of a job is it on these cars?
Thus far I have picked up a vacuum pump and a good quality A/C manifold set. I don't see a reason to flush the lines on this job, but I'm going to pickup an A/C flush can next as I need to replace the compressor on my K3500. That will be my second A/C job.
#9
Join Date: Nov 2007
Location: Eastern PA,
Posts: 10,462
I would not put shop air to a full AC system. I am not sure what that would do to the valves in the compressor. You can pressurize componets like the evaporator.
When ever you check for leaks you want to check the system on and off. System On focus on the high side. system Off focus on the low side. Low side pressures can reach 120PSI when the system is off but as low as 30 psi with the systems on. I assume you are using a black light with the dye? Remember you are looking for traces. If an o-ring is just dripping on the road it my only show a small ring of dye around edge of the fitting. Two places to focus your search. The condensor and the compessor line in the back of the compressor where the pipes go around the sharp turn and the connection to the compressor itself. That main line and the condensor make up about 90% of the leaks I have seen.
The main reason for a flush is a failed compressor, A fail Dyer (thats a mess) or a system that has been disconnented for a while. A leaky o-ring that allows pressue past it is not likely to let dirt in.
When ever you check for leaks you want to check the system on and off. System On focus on the high side. system Off focus on the low side. Low side pressures can reach 120PSI when the system is off but as low as 30 psi with the systems on. I assume you are using a black light with the dye? Remember you are looking for traces. If an o-ring is just dripping on the road it my only show a small ring of dye around edge of the fitting. Two places to focus your search. The condensor and the compessor line in the back of the compressor where the pipes go around the sharp turn and the connection to the compressor itself. That main line and the condensor make up about 90% of the leaks I have seen.
The main reason for a flush is a failed compressor, A fail Dyer (thats a mess) or a system that has been disconnented for a while. A leaky o-ring that allows pressue past it is not likely to let dirt in.
Last edited by Gorn; 06-24-2010 at 05:14 PM.
#10
Also, I've read that the system should be under vacuum for 30+ minutes. Does that sound right to you guys?
And...are there any prone problems with the A/C systems on these cars? I can not find an obvious leak via using the dye. I'm going to replace the orfice, dryer, all o-rings, and schrader valves. If it doesn't hold a vacuum, then I don't really know where else to look. Any quirks on these cars?
Compressor/clutch still good. Last summer I was able to limp it along by charging it twice. Each time it took just a little freon, not much. This summer it won't last more then a day or so. Hoping it is just a bad o-ring or schrader valve.
Compressor/clutch still good. Last summer I was able to limp it along by charging it twice. Each time it took just a little freon, not much. This summer it won't last more then a day or so. Hoping it is just a bad o-ring or schrader valve.
My point is, just don't overlook the compressor itself because it provides cooling...