R134A to ??-12 and compressor oil - PeachParts Mercedes-Benz Forum

JimmyL · #1 06-07-2006, 03:22 AM

OK, I am going from R134A to some kind of "12". So I have pag oil in the system of course. Well, I can flush my evap, condenser, hoses, etc.... And I can and will replace my rec/dryer and my exp. valve. So, here is where my question starts:
I'm was thinking of using the compressor in the wagon now, and holding on to my new reman sitting on the bench. Reason being, my issue was loss of freon, then an apparent blockage of the exp. valve. My compressor seemed to be working fine. Also, with the nice electronic heated pentode sniffer I borrowed, nary a leak anywhere near the compressor, or anywhere else for that matter....

Can I somehow get all the oil from the current compressor, or will I have to go ahead and install the new compressor, and save this one for another R134a system down the road.
My new flush gun from ebay was crap (Robinair too? I was surprised it was crappage), so I'm gonna have to find another way to flush now.
With the "??-12" freon, what oil should I use that I can acquire locally. I know mineral oil, but are there better alternatives?
Thanks once again.

**I wish our search function allowed us to combine words in the search fields. It would save so many questions, as sometimes there is simply too many search threads to fight through**

##I'm up late cause at 2:30 in the morning I'm having to water the yard! We're already on stage 3 water restrictions, and can only water with sprinklers on Tuesdays, between 11:00pm and 6:00am........

tangofox007 · #2 06-07-2006, 09:00 AM

Quote:

Originally Posted by JimmyL

My new flush gun from ebay was crap (Robinair too?
..

I hate to hear that. Especially since I ordered one, too, along with a vacuum pump. Based on your earlier recommendation.

As far as removing the old oil from your compressor, flushing with any type of solvent is not recommended. Drain as much of the old oil as possible, then flush several times with mineral oil.

Mismost · #3 06-07-2006, 10:06 AM

JimmyL...I don't know the answer to your question. What I am wondering is "Why not put the new compressor on the car?". You've spent a lot of time and effort on this project so far, you have the compressor...what do you gain by having the new compressor sitting on the garage shelf?? A reason to doubt the old one?!

I would install the new parts and then clean up the old compressor as time allowed.

It's summer, it's Texas, It's hot, and gonna get hotter...your call.

JimmyL · #4 06-07-2006, 12:22 PM

Quote:

Originally Posted by tangofox007

I hate to hear that. Especially since I ordered one, too, along with a vacuum pump. Based on your earlier recommendation.

I am very sorry about that! I think the vac pump will be fine, but unless I'm just brain dead, it is simply a puzzle for me to get the gun pressurized. Robinair is a very reputable company (the manufacturer) and the gun is physically well made, but if I can't get it pressurized, what's the point.
I'm waiting to hear back from the seller. Allot of folkes are selling this same gun, just not as cheaply as the link I supplied.
I'm very sorry if the product is crappage, and if based on my recommendation you are out some $. At least you have 2 folks to be angry with.....

Let me know when your's comes in, and what you find. I was planning on getting that vac pump also.

JimmyL · #5 06-07-2006, 12:27 PM

Quote:

Originally Posted by Mismost

JimmyL...I don't know the answer to your question. What I am wondering is "Why not put the new compressor on the car?". You've spent a lot of time and effort on this project so far, you have the compressor...what do you gain by having the new compressor sitting on the garage shelf?? A reason to doubt the old one?!

I would install the new parts and then clean up the old compressor as time allowed.

It's summer, it's Texas, It's hot, and gonna get hotter...your call.

Mark, what's wrong with you!!

Why on earth do you want to go and make so much sense with so many good points?

New compressor it will be, and save this one for the jalopy 240 manual I will get some day.....
Thanks for talking me down off the ledge.

leathermang · #6 06-07-2006, 12:34 PM

Jimmy, How about pictures of your flushgun...or link to site and specs on the one you have... can't imagine Robinair not having a good flush gun...
Perhaps it is not intended to be pressurized.. but is meant to gravity flow into a nozzle hooked to Nitrogen or Co2... it would be very easy to have a bad accident if pressure got out of control and blew the flush can apart... in your face.... Greg

tangofox007 · #7 06-07-2006, 01:05 PM

Jimmy,

I have an aerosol-type can that is designed to be filled with pressurized air similar to the flush gun. I found that you really need to leave a lot of space in the can for the air or it doesn't work very well. The instructions say to fill it 2/3 with liquid, but less is better. Don't know if that relates to the problem that you are having, though.

The Ebay seller in question has great feedback. But I found it interesting that I received an email two hours after placing my order which reported my order had shipped. Three days later, they say they still don't have a tracking number available.

Another thing that I found interesting: most of the lower end vacuum pumps look similar, like they all came off the same assembly line. There are cosmetic differences in color, different handle arrangements, etc. But if you look closely, seems like Robinair, FJC and ATD pumps are all genetically related. And Chinese was probably their first language.

#8 06-07-2006, 01:26 PM

Quote:

Originally Posted by JimmyL

OK, I am going from R134A to some kind of "12".

If you use one of the hydrocarbon based refrigerants you don't have to worry about getting all of the PAG out. I don't think the PAG will mess with the mineral oil... correct me if I am wrong.

I would get out as much PAG as you have effort for... it is hydroscopic afterall.

EDITed for more info: It is the chlorine in the R-12 that does not get along with the PAG.

leathermang · #9 06-07-2006, 02:09 PM

The word is Hygroscopic...
Jimmy is smart enough not to use a hydrocarbon gas.
that " some kind of -12 " .... since some of those are really 134a blends.. you need to wait until you make up your mind as to the exact refrigerant you are going to use before choosing the oil ....

JimmyL · #10 06-07-2006, 02:36 PM

Quote:

Originally Posted by tangofox007

Here is the one that I ordered:

http://cgi.ebay.com/ebaymotors/Robinair-Automotive-Flush-Gun-Kit-R12-R134A_W0QQcmdZViewItemQQcategoryZ63700QQihZ002QQitemZ4647178378QQrdZ1QQsspagenameZWDVW
It's definitely designed to be pressurized.

That is the exact one that I purchased. It has a Schrader valve on top, but the outside diameter of the fitting doesn't seal while utilizing an inflation fitting (ie: for filling tires).
The only way I got a little pressurized air in there was to use my blower nozzle, and when I get less than 30 psi the schrader leaks. You can't get much flushing done like that.
I've decided to go the Freeze 12 route at this time. First, it is cost effective, and I fear the leak since I never definitively found mine. Second, I can get it easily. Third, these folks getting good vent temps can't all be smoking crack, so it is working for somebody. Fourth, by going Freeze 12, I can always, and much easily, change to R12, with only a drier replacement at that time.
Not "the best" route to go, I know, but the best route for me........

leathermang · #11 06-07-2006, 02:50 PM

Since Freeze 12 is mostly R134a why don't you just go with that ?
I would use the old compressor with the Freeze 12... have you noticed even in the last few days how many people said their cars compressors lasted a couple of years ? And that has been the trend for several years here... and they say the same on the big sites like Aircondition.com....
The Delco is not as strong as the old York.
Have you taken all the joints apart and installed the proper orings with the proper color Nylog ? ( note, the Nylog should also match the refrigerant you are going to use )... So unless you know which was used you may be inviting short life in terms of your system being sealed... which has the potential for a slow loss of oil which could doom your compressor without you even being aware there is a problem....

leathermang · #12 06-07-2006, 02:53 PM

The valve on your flushing gun indicates that they expect the pressure to be provided through the normal AC guages... or from a nitrogen type regulator off a nitrogen bottle. It also means that you have constant controlled pressure intead of it decreasing as the liquid is propelled out.

JimmyL · #13 06-07-2006, 03:05 PM

Quote:

Originally Posted by leathermang

The valve on your flushing gun indicates that they expect the pressure to be provided through the normal AC guages... or from a nitrogen type regulator off a nitrogen bottle.

I'm not following......
The fitting has nothing for any type of fitting to "grab" and hold on. It is just a smooth outter fitting with an inner schrader valve. It would be effective if something connected to it and held it, which would give constant pressure until the flushing material was expelled.

JimmyL · #14 06-07-2006, 08:44 PM

I feel much better now.

I had an old schrader valve core laying on my work bench, so I removed the one from the gun and installed my used valve core. Gun now works as it should, pumps up and holds pressure. You just use a regular tire filling fitting as one would expect.
The seller in the auction I got the gun at left me an email with a phone number to call them direct, but they were closed by the time I called. The guy that answered their phone also gave me the phone number to Robinair for their tech support.
I knew I liked those sellers.
Now, I would probably still order the other gun style, as you don't have to keep pumping air into it, just remove top to refill flushing agent.
All in all, I'm happy with it, and have flushed horrible looking stuff from condenser and evaporator already. Evap was really dark liquid. Expansion valve had a wad of crud in it that I believe was clogging it.
I still have to remove compressor and flush that line. It is moving along, and I'm back out to the garage.

JimmyL · #15 06-08-2006, 12:18 AM

Just came in from the garage to brew another pot of coffee and read a few posts before I head back out there. Good grief this is quite the involved job. Got really dark and nasty flush out of the evap, and the condenser didn't have the cleanest bowels either.

I flushed one hose, then blew it out with the compressor, and it didn't come out where I had prepared (forgot I undid it top of engine). Well I blasted flush and oil charge all over the motor, windshield, garage etc..... Oppps

And to top it off, a possum wandered into the garage while I was laying under the car. From under there it looked like a prehistoric beast!

Can you point to the pic that might give a hint as to my anal-retentiveness? (have to compensate for the lacking memory also).