AC service possibile conversion

[Spun4Fun]

OOh am sure we used PAG oil about 4 OZ of it as i looked it up and the can is the same one we used , Now since am re doing things can inject Ester Oil ..? there is a sticker on top of the compressor show it's R12 and R134 compatible if that makes any difference unless that is relevant

I am doing it my own way this time not my friend cut corners way .the R134a Was free .I am Out can of Oil and Blue $1.99 Orifies tube so far .

 

[OLDBULL8]

I'm sure not a refrig service expert, but you want to get as much oil out the system before adding more on your next redo. The oil is carried thru out the system by the refrigerant, too much oil might choke the system. As far as charging the refrig in the system, to hell with gauges, charge til the low side frosts at the accumulator at around 80*F ambient, release refrig until it disappears back into the firewall. Man, there's going to be a lot of comments on this.

 

[Spun4Fun]

Will hock an AC recovery system to pull the R134 and save it , Last member mentioned something about ester Oil Vs PAG oil . I know we intialiy used PAG oil about 3.5 to 4OZ . Do i need to re oil the system with PAG , Ester or NON at all


Oldbull8 .. I am going to charge the low side and wont stop until i see snow flakes around the line.

 

[franklin2]

I tried to do some research on the oil thing. Here are some sites I found;

http://www.e38.org/pparish/oil.htm

http://www.autoactech.com/issues.htm

So far it seems the ester oil is most often used in retro fits like you are doing, but if you have the PAG in there, I guess you can leave it and run it. If anyone finds out more about this please post it.

 

[chris142]

You need a lot more oil than that! You want 3.5oz per pound of r134a.mine holds 2.75 lbs of r134a and about 9oz of oil.ester is preferred over Pag in a retrofit unless you flush and start clean

 

[The Bus]

What little experience I have with Auto A/C is that most compressor change overs require you to measure the amount of oil in the old compressor and then add at least that amount to the new one if it does not state that it is pre-filled. I don't why this turns out to be such a odd thing to find out at time given how many A/C compressors out there.

As far as draining the compressor, I could not tell you. These things very by model number (1/2 year changes and what have you not).

By the way, you should flush your A/C components; condenser and evaporator individually and bi-directional to remove any foreign material (metal - you would be surprised) and/or residual freon that may be left. Pressure test for leaks and distortion (tech showed me this on one his shop years ago) Everything else (hoses, orifice tube, o rings, accumulator/dryer) should be replaced as part of changing over.

Chances are the hoses have deteriorated on the inside if your A/C has been down for a while. The systems become acidic once contaminated and will erode the aluminum parts. I learned that lesson when I repaired an A/C on '71 Ford LTD for my Dad years ago.

Just my $.02 worth.

 

[chris142]

The idea behind draining a compressor is to put the correct amount back in to the system.but he's retrofitting to a different refrigerant and the old mineral oil is not compatible with r134a. He needs 3.5 oz per pound of r134a comparable oil.

 

[The Bus]

The idea behind draining a compressor is to put the correct amount back in to the system.but he's retrofitting to a different refrigerant and the old mineral oil is not compatible with r134a. He needs 3.5 oz per pound of r134a comparable oil.

Is that amount a standard ratio?

The reason I asked is that I am planning to retrofit my system and I could not get a definite ratio other than measuring the amount of oil in the compressor itself.

The Bus has a rather large system and I wanted to make sure I had all my information correct before I changed it over.

Thanks.

 

[Spun4Fun]

We have a freezing cold system now . I needed a glove and snow hat .

Here is how it went down .. I bought new accumulator /Drier , Evacuated the System from the previously day old R134a. I pulled the line as i was pulling the blue Orifies tube which had seen less the 20 minute use it had some dirt in it and that was dead give away that it's time to flush , Scrub and make it squeaky clean as i am not doing this for 3rd time ...

So i flushed the system completely clean with AC flush system and compressed air ( Nasty messy job ) . fitted all new O rings and the new drier ,Added Oil equivalent to 6 Oz , Added Orange Orifices tube ( The part store show Orange tube for 91 model and Older or for GM cars ) ,Pulled vacume for over an hour maybe more as i lost track . System passed with green flags ..Zero leaks . I added 2lb and 12 Oz as recommended plus 3.5 Oz of oil . AC on high and baaaam .

All the great info and experience's you guys posted here allowed me to make an educated decision under the hood to get this Green machine AC working like it should for this racing weekend trip..

 

[mu2bdriver]

Good work. How many o rings does the system have? Do you remember of hand?

 

[Spun4Fun]

2 Big O rings at the back of the compressor , 5 for the lines , 1 small by the AC pressure switch and another small one by the fill valve ( These small ones are on the drier fitting) So total of 9

 

[mu2bdriver]

Perfect. Thank you. My o-ring kit should be coming in today with the rest of my goodies.

 

[chris142]

Is that amount a standard ratio?

The reason I asked is that I am planning to retrofit my system and I could not get a definite ratio other than measuring the amount of oil in the compressor itself.

The Bus has a rather large system and I wanted to make sure I had all my information correct before I changed it over.

Thanks.

Yes when doing a retrofit to R134a from r12.

 

[Ruger_556]

If you have a tight system.. add some refrigerant stop leak, and R12, to get the required hi/lo pressures.

To anyone reading this do not do that ^^^

 

[HS108]

Where did you order this orange orifice tube you speak of?