PAG oil hygroscopic-ness

[exranger06]

What you're seeing is where my accumulator used to be. It's been left like this for about a week. It's not air tight, but it's sealed up pretty well. I just put fresh PAG oil in the compressor last weekend. My question is, did the PAG oil absorb a ton of moisture in the past week by leaving it like this? Should I drain and refill the compressor again? Or would vacuuming it down be enough to get rid of any moisture?

 

[LeakySeals]

Yeah drain and fill. Compressors like new oil too. You will find less engine chugging sitting at a stoplight w/AC on with new PAG. Just like the engine, fill accuracy is important.

 

[exranger06]

It does have new oil in it, I'm just worried about it absorbing moisture over the past week. Would like some more opinions before I start tearing it apart (again) in a few hours.

 

[mechtech2]

How did you get all the old stuff out and know how much to put back it?
That is a TOUGH one.

 

[exranger06]

I removed the compressor and drained it out. I put the same amount back in.

 

[mechanicx]

I'm going to say since it's only been a week, sealed it off and I assume you installed a new drier and will pull a vaccuum on it that the oil will be OK to go with.

 

[Rock_Hudstone]

I taped off the hoses most of last winter on the GF's car when a temporary bypass pulley was on there. When the new compressor was installed I evacuated/charged the system and it worked as well as before. However, I had it sealed up super tight with electrical tape.

Did your system absorb some moisture, probably, but not enough to justify tearing it apart to replace the oil, which you won't get all of anyway and will expose the system to the atmosphere even further.

I would add whatever oil is necessary, then evacuate the system for at least 45 minutes.

 

[RH+G]

Depends on which PAG oil was used. DOuble End Capped PAG oil doesnt asorb moisture. If that was used then dont worry bout it.

 

[mechanicx]

Good point. I think double end cap PAG is really common now and I think it is blue and the other stuff is green, but I'm not 100% sure.

 

[exranger06]

What is "double end capped" oil? Never heard of it. I used PAG 46 with UV dye in it.

 

[mechtech2]

There is oil in other parts of the rest of the system - all the oil is not in the compressor.

 

[wtd]

PAG oil will absorb moisture pretty easy if it is exposed to air so it all depends on how tightly you have those ends wrapped off and how porus the material used is.

Vacuuming down the system will remove moisture from the system so you may be ok since the lines are not totally exposed and you have not have the ends taped off for that long. The safest bet of course is to replace the compressor oil with new that way you don't have to guess how much moisture might have gotten into the oil.

Wayne

 

[RH+G]

Double end capped is the second generation of PAG oil. They dont absorb moisture like the original PAG do.
If u stil have the bottle it should say it on the bottle.