auto a/c. pag oil question

P49Y-CY

fomocomofo
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i am going to recharge the system in my 2004 F-150 with refrigerant (r134a). the system is currently empty. it was discharged by a shop a couple of months ago.

prior to this, the a/c was working, but it did not feel like it was blowing quite as cold as it had been. cool, but not really "cold", esp on very hot days last summer.

i have a manifold gauge set. the system holds a 2 hour vacuum overnight. it has never been "opened" or any of the components replaced.

do i need to add pag oil in this situation?

in other words, did the evacuation/discharge/recovery process at the shop also remove the pag oil? is there any way to tell how much is in there right now?

system capacity is 8oz. and i want to try to get it to that.

thanks
 

MG0h3

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The oil should have stayed in the compressor. But Ive only done back yard AC work and not used a machine to evac.

Just make sure you have a good vacuum on it prior to fill


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hotcobra03

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I wondered also. But from reading ,,installing a compressor you can add oil before install.

I don't see any oil blowing out my vacuum pump when it's running.

I'm also not a ac tech
 

olympic

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You generally don't lose PAG oil when venting the system through the filling valves. I'd just evac the system and refill it with the proper amount of R134a.
 

derklug

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Our machine usually removes .15-.5 of an once of oil on a recovery. We add back .5 oz. typically because our oil also has die in it.
 

Crimson2v

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Many machines will remove some oil at the end of the recovery process. I usually measure it out and then put it what I removed. I would add a little to be on the safe side.
 

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