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Discussion Starter · #1 ·
Howdy y'all!

While driving down the highway a week ago my A/C decided to give up the ghost, including being able to receive air from the dash vents. After a little exploratory surgery I discovered that the vacuum actuator for the dash vents decided to break off from the mounting tabs. Furthermore, the actual mounting tabs had actually broken away from the main box due to a botched repair job from the previous owner. So, I got to try my hand at plastic welding this last weekend, and I was successful in re-attaching the mounting tabs to the box and everything fits perfectly and has a very strong bond (saved myself around $300 from having to source a new HVAC box top).

On to my question, since I had to pull the HVAC box out I decided to replace the evaporator and heater core (obviously). The evaporator is the original to the vehicle (23 years old). Which led me to decide to replace the entire AC system, including all the lines, compressor, condenser, and receiver/dryer. I am a die hard do-it-yourself kind of guy and will be doing this myself. My research has concluded that I need 8.1 oz. of PAG 100 oil and 20 oz. of R134A. What I can't figure out is where to add the oil to the compressor and will it hold all 8.1 ounces? Is there a process for adding the oil or a special procedure? I know how to add the R1334A after I vacuum down the system, it's just adding the PAG oil I need a little advice on.

This project will be done in my driveway, utilizing a vacuum pump and a proper manifold gauge set.

Thanks for your help
 

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Since you have the system open, check the compressor and see if it has a removable plug on the top. The Sanden compressors do. If so, pour it in the crankcase of the compressor and replace the plug. That is the way new compressors come
 

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Discussion Starter · #3 ·
Thank you for the reply. I located the oil plug on the compressor.

I have found out that the Murray compressor I am replacing comes from the factory with a total of 3 ounces of oil pre installed. This leaves me with a total of 5 ounces that I have to add to the system for the factory rating of 8 ounces. Do I add this oil to the compressor, or to components that I am installing? If the components, which ones and how? If the compressor, will it hold all 8 ounces without overflowing? I don't want to cause failure due to over/under lubricating the system when I do this.
 

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Discussion Starter · #7 ·
Now you're telling me to add it to the accumulator (aka Receiver/Dryer)? I'm getting confused. Every item in the AC system is being replaced. So do I add PAG to any other component other than the compressor?
 

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The oil does not stay wherever you put it. It dissolves into the refrigerant and lubricates the pump as it is circulated. It is not like an engine crank case. The rings are an oil ring. so if you have any in the pump crank case it is eventually forced out as the crank case becomes pressurized.
 

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Discussion Starter · #9 ·
Update: I was able to replace all of the components and got it running without issue. I noticed that the air flow through the cabin has increased and the air is cold enough to freeze you out. The wife is happy and will now ride around in the Jeep with me. Thanks for the help and technical advise.
 
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