Adding Oil to the AC System
One thing I haven’t mentioned yet is putting refrigerant oil in the system.
You normally do this when recharging the system after replacing one of the major components. This is tricky. The service manual normally tells you how much refrigerant oil should be added with each major component replaced on the AC system. You need to be very careful during this process.
Many people ask what refrigerant oil actually is: Basically, it is a specialized oil meant to be used in your air conditioning system that is engineered to run smoothly through all the moving parts.
*For more info on recharging your AC system, you can try this page.
The thing is, most replacement components, such as compressors, often come with the prescribed amount of oil already in the part. If you add oil on top of this, you might saturate the system and it won’t work as well.
In addition, it’s not a good idea to mix R134a refrigerant oil with R12 oil. This becomes an issue if you’re retrofitting an AC system. On top of that, it’s difficult to add oil to the AC system with DIY tools. Professional AC equipment comes with provisions to add the correct amount of oil with each charge. Off-the-shelf cans sometimes come with refrigerant oil in them as well.
My point here is that if you want to err on the side of caution, don’t add any oil to the system. It’s worse if you add too much and cause a problem. Look for refrigerant cans that have oil already in them. This will be your best bet. Otherwise, make sure you measure out the correct amount of refrigerant oil and ensure it is the correct type before you add it to the system. Here is a video on recharging your AC system, in which I add refrigerant with oil:
I’ll say it again: make sure you are wearing safety glasses when you work on AC systems.
8 thoughts on “Adding Oil to the AC System”
tyrone loukas
April 12, 2024 at 5:36 am
Thanks for taking the time to add oil to the AC system! Your attention to detail ensures smooth operation and prolongs the life of the system. Great job!
John
March 25, 2022 at 11:00 pm
So I have a 07 F150. Had a bad Schrader valve on the hi side and lost all the Freon. Replaced both valves, and I am ready to evacuate and recharge the system. Do I need to add any oil? Only Schrader valve cores were replaced.
thanks,
DAVID
July 26, 2021 at 9:33 am
check zero on gauge’s before starting, adjust if necessary.
glen
June 24, 2021 at 5:19 pm
I have a ’02 Ford Taurus. I replaced the AC compressor and the orifice tube, and I have a new accumulator with hose assembly. I added 3 oz. of PAG oil to the compressor, and I need to add 3.6 oz. more to the accumulator. How do I put the PAG oil into the accumulator ? The hose is going to the evaporator. Do I pour the PAG oil into that hose and let it drain into the accumulator canister ? I don’t see any other way to do it.
Jeff Zerbe
June 22, 2021 at 2:01 pm
Is there an AC machine for 12234 that can add PAG oil like the 134 machines?
Jacob
March 27, 2021 at 8:08 pm
Do i need to add oil if i just replaced a line?
Angelo
July 21, 2020 at 1:19 am
What if you have a r1234yf system and cans with oil in them aren’t available, how do you measure the correct amount of oil? And do you have to add in oil if you just do a vacuum and recharge with no parts replacements? What if the system has oil you replace a part, you add an entire systems worth of oil still?
hotdog305
September 23, 2020 at 6:48 am
no just the amount for that part per the dealer specs