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Where to oil a dry A/C system?

FordF350 on Thu April 03, 2014 12:21 AM User is offline

Year: 2003
Make: Ford
Model: F-350
Engine Size: 6.0
Refrigerant Type: 134
Ambient Temp: 70
Country of Origin: United States

I am replacing all my a/c components and I have a question about where I should disperse the PAG oil in the system before reassembly.

This is a fresh setup, all new components, lines and a Motorcraft compressor. The compressor came with 7oz of PAG 46 in it. My system holds 9oz and I know it needs to be in different places in the system prior to charging and first run.

Where should I disperse the oil? I have read that half goes in the suction side of the compressor, half in the drier/accumulator, but I have read other conflicting approaches elsewhere too..

Also, what brand of PAG oil do y'all recommend? I picked up some "Certified A/C Pro" PAG 46 w/ UV dye from O'Rielly's, but every time I see something with "pro" in the label, I usually run the other direction.

Lastly, I am charging with cans, but I have a digital scale. Any input on a new dry system would be greatly appreciated.

Thanks for the input,


Edited: Thu April 03, 2014 at 6:58 PM by FordF350

FordF350 on Thu April 03, 2014 6:54 PM User is offline

Anyone have any ideas? The only thing holding me up from reassembly is this oil question. Any assistance would be greatly appreciated.



TRB on Thu April 03, 2014 11:20 PM User is offlineView users profile

It really does not matter in this system as it will be moved quickly when the system is running. Accumulator is a easy place to add a couple ounces of oil.


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mk378 on Fri April 04, 2014 9:09 AM User is offline

It is common practice to drain and replace the oil that comes in a new compressor, because it may have been contaminated with water during storage and shipping. They put the oil in because of people who don't know what they are doing at all will ruin a compressor running it without oil then expect a warranty replacement.

Put in as much refrigerant as you can as liquid before starting the engine the first time. This will ensure there is something to keep the oil moving back to the compressor after it starts.

Leggie on Tue April 08, 2014 7:23 AM User is offline

The oil doesn't need to be added. New compressors are filled with oil and shipped with with caps that hold the ports airtight. Push the spec value into the high side as liquid and call it done.

FordF350 on Fri April 11, 2014 1:39 AM User is offline

Thanks for the responses. I went with mk378's advice and changed the oil. I am glad I did.

And Leggie, the compressor for my truck only shipped with ~7oz of oil, but the system requires 9oz.

Thanks again everyone!

HECAT on Fri April 11, 2014 4:10 PM User is offline

I am glad you went that route. We can assume it has the right amount of oil in it, or we can drain (IMHO-the shipping/storage oil) and fill with fresh; just to be sure. We have been bitten so many times by what "they said"; that we always look for ways to validate and verify for ourselves.


HECAT: You support the Forum when you consider for your a/c parts.


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