How To Add PAG Oil Into An AC System

If you've just completed an AC repair that requires adding compressor (PAG) oil to the AC system, your AC vacuum pump can be used to pull the oil in (via the AC Service Port) with no fuss or mess. I've found this to be easier, faster and cleaner than pouring oil into your new condenser or accumulator. Just attach your pump to the low pressure port, remove the schrader valve on the high pressure port, turn on the pump and let the air suction from the HP port suck in the oil via a rubber tube between the port and oil bottle.
If your ac system has been suffering from a leak, some PAG oil is lost and must be replenished. This is why many of the 12 oz freon cans come preloaded with 1 oz of oil with some type of stop-leak component. So you're basically getting 11 oz of refrigerant instead of 12. The evacuation does not pull the remaining balance of oil out of the system. When you recharge the system after replacing the component that has failed, you need to add oil to compensate for both the lost oil from the leak and the oil lost residing in the replaced component. This is all guess work. If you want a perfectly accurate amount of oil to reside in the system, then you need to have it evacuate and recharged from a professional evacuation and recharge machine. Another method is to take the compressor off (if not the source of the leak and not being replaced), measure out the amount of oil in it, then calculate the amount of oil needed to bring the amount of oil needed to bring it to the manufacturer's specs. I one time ruined a replaced compressor because I didn't add enough oil to compensate for lost oil from a replaced evaporator. The oil acts as a coolant for the compressor and lack of oil will burn out a compressor.
After the PAG oil has been added, reinstall the schrader valve and pull a vacuum on both the high and low pressure quick connect ports. Check the gauges and see if you're close to -29 psi with the pump off; if the needle slowly heads back towards zero, you have a leak somewhere. If no leaks, pull vacuum for around 15 to 30 minutes. This should remove all residual moisture in the system. Afterwards, you're ready to introduce your refrigerant.

Parts & Specialty Tools:

Windshield Washer Hose Kit (can use between PAG bottle and service port)

Air Conditioner Leak Detector Tool Flashlight Oil & Sniffer

Automotive Heating & Air Conditioning Haynes TECHBOOK

AUTO AC Repair Complete Tool Kit with 1-Stage 3.5 CFM Vacuum Pump, Manifold Gauge Set, Hoses and its Accessories

TSI Supercool A/C Comp PAG Lube, 8 Oz, Flash Point 442 F

Valve Core Remover with 20 Pcs Schrader Valve Cores Dual Single Head Valve Core Remover Tool

41Pcs Car Air Conditioner Valve Core Schrader Valve Cores Accessories A/C R12 R134a Refrigeration Tire Valve Stem with Double Head Dual

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#pagoil #addingpagoil

[patrickzadd]

for many years
your videos have been very helpful for me
thank you

[testuser]

This is sheer beauty. Glad I found it!!

FYI, . I don't think this will work well on systems with TXV vs. orifice tubs, because a TXV system may not equalize well or at all, but I suspect on an empty system of any sort, if you can feel a vacuum at any specific port, you can use it to pull oil into the system using this method.

I have a few bottles of PAG46 oil with dye and 2 R-134a systems I need to work on, but my father-in-law's Cadillac has so much crap covering up the engine guts that I am really not looking forward to digging into it, but I know it has a slow leak, and needs oil, 'cause his "mechanic" just keeps adding R-134a every few months, or when there's a complaint, saying that the real problem is too hard to fix, or won't be worth fixing... I'll get some dye into it (with oil), and see if I still agree with them about that part. Either way, the system will need much more than Freon if no one ever adds oil to it, so I'll try to save the compressor from an early death without taking everything apart.

To all the armchair QBs who are ranting about bringing moisture into the system, go read a book, and avoid AC repair, 'cause you don't get it. The system was already open to the atmosphere, so the damage is done, and that's why you pull a deep vacuum on the system, and let it sit for a while - to evaporate the remaining moisture and remove it! And also why you do that AFTER doing this!

I nearly bought one of those fancy oil injector tools from Amazon before I saw this, and I'm really glad I did!

[MadClowdz]

THANK YOU! I just replaced the low side Schrader valve and condenser/drier in my '01 Highlander, and I thought I made a mistake adding the appropriate amount of PAG oil before purging the system and adding coolant, but you answered my question! My AC held steady -29 vacuum for over an hour! 20 min left on the purge, then fill with 24 oz of R134a, which is according to official capacity specs, and my AC should be better than it's ever been since I bought this car 3 years ago.

[radmilakrejci]

This is absolutely awesome idea! To prevent future comments you should edit your description under video and say, after adding PAG oil into the system, make sure to evacuate for at least 30 mins or so to draw moisture/air out of the system before recharging AC.

[cybco]

That kinda works, but you get air and moisture back in that way. Another way is to hook both H and L hoses up while off. Pull a vacuum while opening the H and L values slowly. Once you get a vacuum shut both values off. Pull yellow hose off vacuum. Poor whatever amount oil you need in yellow tube til it reach peep glass that forces most air out. Put a freon can on yellow hose, and open both H and L values which will bet forced oil into their chambers.

[danjohn]

I hope you’re getting something out of these videos. At least some pride knowing you’re helping people out. You saved me some money. More importantly, you gave me the confidence to do this correctly myself and I got some awesome tools out of it. 🤓

[thorthunder]

Does teh air compressor have a filler port? If so, then why not put it direct to the compressor with a fitting and tube for suction and eliminate a migratory problem which might not be able to migrate out of the condensor or where ever the oil travelled to?

[hostilityy]

if the system is empty why not add oil by pouring in the line then connect the refrigerant can when you're charging it?

[Whatru]

I have a 1995 Chevy Cheyenne C1500 pickup. I replaced the compressor, condenser, accumulator and all the lines. I brought a oem compressor and it has a sticker on it that says (Note: 7.0 oz PAG 150 oil added.) The system holds 8oz. Should I put compressor in and spin it 20 times to lub the compressor and then add an oz to the accumulator, vacuum the system and then charge it?

[robertc]

I've always drained the shipping oil out of the ac compressor and added the proper amount before install the compressor then pull a vac

[marcelfilms]

pro tip put the hose into the bottle before starting vacuum pump to avoid sucking moisture

[DaisyRose]

If my compressor is humming when I turn on high do I need oil or an new compressor

[All-about-everything]

I think I put too much pag oil in my A/C after new compressor and condensor. When I push the low pressure it squirts and bubbles out. Also when I hit the high for 1 second lots of fluid on my hand drenched. How do I remove some oil

[eugenepool]

If I'm only replacing an orifice and expansion valve should I put in the original amount of oil that the system requires or will some of the existing oil stay in the system after reclamation of the original refrigerant?

[drcoffee]

What a spectacular idea. Wish I thought of it 6 cars ago. 😀

[giocarrepair]

Hello after adding oil if i continue to do vaccum to the system about 30 min the oil added get out with the vaccum (moisture )or stay in the ac hoses system????

[rexmiller]

This is an excellent idea, I would never have thought of it, thank you.

[davecc]

"Based on that big leak we have to introduce around 3 ounces of PAG oil." How do we calculate the quantity of oil needed for a given leak? Is there a formula? Some calculation?

Won't the PAG oil be sucked out of the AC system into the vacuum pump?

[saadalghamdi]

Good job thanks . But how can remove old oil . Or when open pipe 134a ar old is gone withe. Thanks

[tommykun]

So if I flushed my entire system of oil, could I simplify add all 8.5oz of oil my system require using this same method, by suction using the high side line?