Still working on the A/C...

Now that the system has held a vacuum for a couple of weeks.... (darn
I'm lazy)
I figured its time to load it up with freon and see how it goes.
The only components changed out were the condensor, o-rings and
schreader valves.
I never really noticed any PAG oil come out of the system. Could this
have been sucked out when being vacuumed down?
I've seen where the suggested amount for the whole system was 6 ounces.
Does the oil usually remain in the compressor or does it constantly
circulate throughout?
I looked for a charge can with PAG at Autozone - I think it held only 2
oz.
I looked for one at Wally Mart and it had 9oz with 2oz of freon.
I asked the guy at Autozone and he showed me liquid PAG in 10 oz
plastic bottles..
(and there was viscocity of 70 and of 150 and also of ESTER oil (?)
As far as which to use and how to apply - the "friendly experts" HAVE
NO CLUE.
Please. What do I use?!
Do I add oil to the compressor? Forget about the vacuum and start over
again by opening the system from the back of the compressor?
I'm a little lost here.
I could have done a more thorough job but I'm slow enough as it is and
probably should get this vehicle back on the road. (WAY too hot in
Texas to travel without A/C!)
Thanks Guys.
-WaV

 

It will not get sucked out. Ad a ounce ot two if it make you feel
better but do not ad full amount as too much can ruin compressor.

 

Agreed.
I also read today that PAG oil is hygroscopic - that it absorbs
moisture.
When moisture combines with 134a, it forms hydrochloric acid.
Conclusion: good thing to have a dry system!
Perhaps draining the old oil from the compressor and replacing it with
new might not be a bad idea? (especially if I'm too lazy to replace
the accumulator/dryer?)
And would low viscocity oil be preferable over the 150 oil?
And what IS ester oil?

-THANKS AGAIN

 

I think it's very self defeating to do all that work and then (through
laziness) NOT change the drier.....

 

Yeah... well all I really did was replace the schreader valves, put on
a new condensor I paid $10 bucks for on ebay and vacuum it down.
I dont really even know if the compressor is going to work. I dont
want to use a perfectly new dryer if this isnt even going to work.
If I replace the compressor - definately, I'll replace the dryer.
-WaV

 

*shrug*

Pay now or pay later. Better to just do it right the first time.

Cheers,

 

When you vacum it down and hold it for a while it will pull the
moisture out. PAG is poly-aklylene glycol (R134a will not mix well
with mineral oil) and Ester il (polyol ester) is a synthetic lube that
will work with R134a too. Because PAG is glycol based (like anitfreeze
and brake fluid) it will aborb moisture if given a chance too.

 

Not if you don't change the receiver/drier. Once the dessicant in the
drier is saturated with moisture, it becomes useless. Taking it down to
a vacuum MAY help a little, but it's not going to solve the problem.

It is good practice to change the drier any time you've got to expose
the system to the atmosphere (such as changing the condenser).

 

Correct, plus what happens if that old dessicant bag falls appart?

Wavy you can get much better help by going to a auto ac forum because it
will have more knowledgeable people in ac service and less average joes
giving you lacking or bad advice.

www.autoacforum.com Research your questions before you ask something
that might have already answered and be sure to give them as much detail
in your first post when you do post there.

 

Somewhat true but if you oull down and hold a good vacum for a while
it will remove a lot of the moisture.

No aurguement here, especaily with a compressor change that has
trashed out because it acts as a filter of sorts to and replacing it
gets the trash out of the system.

 

No always true. You get good advise where you can find it just like
repair shops because not all of them really know what they are doing
as I have seen some "dealers" mess things up.