A/C gurus...please help!
07-08-2006, 04:40 AM
#22
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RE: A/C gurus...please help!
ORIGINAL: FiveLiterRiceEater
no. you'll want to evac the system to make sure any comtaminated refrigerant is out. and have a vacuum put on it for 5 minutes to make sure it doesnt leak. then you can fill it to 75-85 percent of the r12 capacity, but fill it with 134a. you only go with 75-85% because 134a will have a higher pressure at a given temp than r12 will. and you can also have them put some dye in the system. this way, you'll have the correct amount, know if there are leaks, and will be able to detect leaks if they come up in the future.
no. you'll want to evac the system to make sure any comtaminated refrigerant is out. and have a vacuum put on it for 5 minutes to make sure it doesnt leak. then you can fill it to 75-85 percent of the r12 capacity, but fill it with 134a. you only go with 75-85% because 134a will have a higher pressure at a given temp than r12 will. and you can also have them put some dye in the system. this way, you'll have the correct amount, know if there are leaks, and will be able to detect leaks if they come up in the future.
07-08-2006, 04:45 AM
#23
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Location: NY
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RE: A/C gurus...please help!
ORIGINAL: FiveLiterRiceEater
not that i dont believe you, i was just told differently. so what will mixing 134 and mineral oil do, and what will pag and r12 do? will the oils just break down?
not that i dont believe you, i was just told differently. so what will mixing 134 and mineral oil do, and what will pag and r12 do? will the oils just break down?
Since 134A & mineral oil dont mix the oil travels mainly along the interior surfaces of the system, including when the refrigerant is in liquid phase. The oil travels slowly this way & tends to collect in the evap where its the coldest. This causes the compressor to run short of oil because u have more going out than returning. Once the car has set in sun, heated up evap w/ 110F+ air this increases gas velocity & thins out oil, it also can cause a large colum of oil to return to the compressor form your evap & accumulator. This will stall or break internal componets.
R-12 will work w/ any oil, so will R-22.
Ester, mineral & PAG oils all ARE compatible w/ EACH OTHER. A 50/50 mix of ester & min will most likely move oil ok. So if you use enough of those kits that contain ester it might work.
Then only thing that will break down the oil is heat.
07-08-2006, 04:58 AM
#24
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RE: A/C gurus...please help!
One more thang. Most leaks on the R-12 systems, retrofitted or not, are from around the compressor seals. The seals dry out from not having oil on them during the winter or long peiods of non use. The newer cars w/ the r-134A use the A/C system to remove moisture from the air when your defroster is on. So oil is on the seals more.
So evacuating & adding refrigerant might work. Dont add 134A w/o evacuating tho.
So from time to time use your A/C for 5 mins to keep seals wet. Once /month is good.
Check your schreider valve cores w/ soap bubbles. Take caps off & use soap bubbles (or some spit) where u attach hose to. If it bubbles then thats prob where leak is. Caps need to be tight w/ good o-rings. Let dry befroe caonnecting any hoses.
So evacuating & adding refrigerant might work. Dont add 134A w/o evacuating tho.
So from time to time use your A/C for 5 mins to keep seals wet. Once /month is good.
Check your schreider valve cores w/ soap bubbles. Take caps off & use soap bubbles (or some spit) where u attach hose to. If it bubbles then thats prob where leak is. Caps need to be tight w/ good o-rings. Let dry befroe caonnecting any hoses.
07-08-2006, 05:05 AM
#25
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RE: A/C gurus...please help!
Seems like you have an incomplete retrofit. The standard Schrader valve you have is an R12 fitting. R134a fittings are quick disconnect fittings & can't be mixed up, b/c the suction(low side) fitting is much larger than the discharge fitting(high side) and the wrong hose won't fit.
You should only charge into the discharge side of the system when it is running because one, it's much quicker and two, you could blow up the can on the high side (it usu. builds 200-250 psi).
You should really invest in a gauge set & a mobile A/C class at your local CC if you want to do your own A/C work.
The discharge lines should only be cold & wet, if they are frosted over, you are overcharged.
Also, if you mix R12 & R134a, it will cool really poorly & send your pressures through the roof.
You should only charge into the discharge side of the system when it is running because one, it's much quicker and two, you could blow up the can on the high side (it usu. builds 200-250 psi).
You should really invest in a gauge set & a mobile A/C class at your local CC if you want to do your own A/C work.
The discharge lines should only be cold & wet, if they are frosted over, you are overcharged.
Also, if you mix R12 & R134a, it will cool really poorly & send your pressures through the roof.
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