Car A/C Question.

[DaPlayer]

Hello, Got a question concerning Adding R134a and PAG Oil.
1999 Dodge Durango, 5.2L. V8.

Question doesn't really pertain to any specific vehicle.

System Capacity in OZ. Is 30 Ozs. Dual A/C.
Oil Capacity. Is 8 Oz's.

Now for the question.

Am I adding 30 Ozs of R134a, and 8 Oz's of Oil?
Or 22 Ozs of R134a and 8 Oz's of oil?
My oil has UV mixed.

Thanks.
DaPlayer.

[iq180]

8oz of oil & 30oz of 134, on the under hood lable it will tell you how mutch oil & freon, so it would be a total of 38oz.
but keep this in mind, if you have not flushed the system to remove the old oil then most of the old oil is still in it, if that is the case then you only want to add about 1oz of oil.

[satchick]

You should still evacuate the system if it hasn't been done, as there is going to be some refrigerant left in the system. You want to make sure that all of the old refrigerant is removed, as R134A...

[murph001]

You Are 100% correct Satchick ,,nice informative post ..

[aquadave]

Why do you want to add oil? that is one of the biggest mistakes I see in DIY mechanics with car AC. Just because you see some oil residue doesn't mean you lost a considerable amount. the ONLY time I add oil is changing out the compressor. Too much oil is not good

[murph001]

you only need to add oil if parts are replaced ..or if servicing removes oil from system when reclaiming and vacuuming ..

[murph001]

Charge with nitrogen find leak ,repair the leak ,some replace the reciever drier as well as whatever part was leaking then vac system for 30 minutes to an hr then if system hold vac recharge system...

[satchick]

The receiver/drier and orifice tube (if so equipped) should be changed every time the system is open to the atmosphere, either from a leak or parts replacement. Exposure to moisture will ruin the desiccant in the drier very quickly. It is considered to be a maintenance item anyways.

When correctly servicing the system, the oil is removed during the refrigerant recovery process. Removing EVERYTHING from the system and recharging by weight is the only way to ensure that the system is filled with the right quantities of oil and refrigerant. Overcharging by even a couple ounces is enough to blow seals, or slug the compressor. Oil and liquid refrigerant doesn't compress so well...

[aquadave]

That's what i'm talking about, A leak doesn't lose OZs of oil neither does purging lines neither does replacing the dryer though it may seem like it, it's so little it makes no difference. A vacuum does not remove oil only moister. The vast amounts of oil are in the compressor and the accumulator. The residue you see that seems like a lot is a fraction fraction of an OZ and will make no difference to the operation of the system. Only change the dryer when changing the compressor and if you do so 5hr vacuum min. 134 and 410 are way more sensitive to moister than 12 and 22 require more of a vac. and when inducing oil suck it in through the high line. After a compressor change I pull a quick vac suck the oil in through the high line, pull a vac on the low line to assure all the oil has been introduced to the system then pull my full vac. I've been doing refrigeration since the mid 70s and I've seen more damage from DIYs using to much oil more than every other mistake combined. trust me unless you're doing a change out don't add oil and do a longer vac. FYI to much oil cuts down your efficiency big time

[rusty121]

approximately 22 percent of the air is watter so when you open the ac system, air rush inside and is that happens you need to evacuate the system. the vacuum pump only takes the air out, so is you have no air you have no watter. Is the system is not leaking or open you donot need to evaccuated the system. when evaccuating the system once you see about 28 to 29 (depending on sea level) inches of vaccun, you have no air, so is no need to continuing pumping or waisting time specialy is you work for a dealer or ac shop, you may lost your job if you pump for 5 hrs.
The refrigerant and oil mix together, so if you have a leak you will lost refrigerant and oil the amount will depend on where the leak is and how big. Anny time you replace the compressor/evaporator/condenser or hoses and some other components or the system is open for a long period of time is recomended to replace the acumulator or drier and the orifice tube is so ship that you should replace that to. When replasing the compressor make sure it have the proper amount of oil, some compressor comes whit the oil and some whit out. When recharging the system make sure you used 2 gauges if you know how to used the low & hi gauges you will know how much refrigerant you have in the system , olso you will know if you have a problem and what the problem is.
Don't forged to replace all the seals that you remove, including in some automobiles the spring looks. and make sure you used the correct refrigerant & oil. it is a good practice to ad Dye.
(Excuse my Spanglish)

[aquadave]

lesson #2 evacuating a system is to remove moister from the system not just air. water boils and becomes a vapor in a vacuum and is removed by vacuum. a "quick vac" will remove air but not enough...

[skatz420]

There is a guide for how much oil to add during component replacement. I think Compressor and Condensor are the most. A/C work is all smoke and mirrors. hahahah