auto a/c. pag oil question

[P49Y-CY]

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]

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]

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]

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.

 

[hotcobra03]

Repair content for 2004 Ford F-150.PDF

Shared with Dropbox

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Adding pag oil

Ac

S42C0012.pdf

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[derklug]

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.

 

[Bullitt1448]

SOME oil always gets recovered with the refrigerant. I would add .5 ounce when filling the system.

 

[Crimson2v]

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.