Universal refrigerant oil - PeachParts Mercedes-Benz Forum

Cr from Texas · #1 03-15-2009, 01:55 PM

I'm rebuilding the AC on my 1983 MB to include, new compressor, new expansion valve, new drier, rebuild lines with 2 ply hoses. A have about 10 lb of R-12 and plan to use that as it reportedly cools best in this car. At some point, I may have to convert to R143a. It looks like there are some oils rated for both R-12 and R143a. If I use one of these and need to convert later, would that eliminate the need for an oil change and a complete flush at conversion time? I'm considering the Auto 100, or FrigiQuiet oil. I think they are both POE type. Any preferences?

Matt L · #2 03-15-2009, 02:05 PM

You won't be happy with 134a in that car, and you'll be especially unhappy in Texas. I would stick with mineral oil and count on the continuing availability of R12.

Cr from Texas · #3 03-15-2009, 02:10 PM

I am sticking with R-12. Question was about oils. From what I've read, there seems to be some synthetics that might be better than mineral oil. As I understand it, R-12 production has stopped in all countries and the supply is limited to what has already been produced. I may begin hoarding R-12.

Current question is oil recommendations for R-12. Mineral or synthetic?

Matt L · #4 03-15-2009, 02:40 PM

I haven't seen anything which leads me to believe that POE is better than mineral oil, but I'm willing to learn.

Ian White · #5 03-15-2009, 02:40 PM

Quote:

Originally Posted by Cr from Texas

I am sticking with R-12. Question was about oils. From what I've read, there seems to be some synthetics that might be better than mineral oil. As I understand it, R-12 production has stopped in all countries and the supply is limited to what has already been produced. I may begin hoarding R-12.

Current question is oil recommendations for R-12. Mineral or synthetic?

When I got the A/C going again on my former 300SD I used R-12 and used the FrigiQuiet. I had good luck and it worked great until a woman t-boned me on the drivers side and all the refrigerant leaked out. That car is no longer existing. My current 300SD has been converted to R-134A and works fine here in the Mild Climate of Washington, in fact I have no real huge complaints about the 134 just that it isn't quite as cool.

But in your case R-12 with FrigiQuiet I think is the best way to go. Mineral Oils break down over time, just as all natural oils do. Synthetic is the way to go.

Just my $0.02 worth.

280EZRider · #6 03-15-2009, 02:56 PM

The US Navy alledgedly still uses R12 in the entire fleet. Lower pressure & higher cooling is the best reason to hang onto your R12. So for those who don't have access, better befriend a Navy guy.

LNGfish · #7 03-15-2009, 04:08 PM

I was told Ester oil can be used for both that you mention. My 1982 300SD has Ester and 134A. I'd go back to R-12 in a heat beat if I was lucky to have some, but R134 isn't that bad where I live in South Carolina.

I checked into it and it checks out. Ester works fine with 134A also since mine has been tight for 3 years. I put the ester oil in the receiver when I was putting it all together. 4 oz I think.

Cr from Texas · #8 03-15-2009, 05:19 PM

Thanks for are the replies. Looks like I'll be able to stick with R-12 for a long time. I just located (via Craig's list) and purchased today, 2 partial drums of R-12. One weighs a total of 28 lbs and the other 21 lbs. Anyone know about what an empty cyliner weighs?

leathermang · #9 03-15-2009, 08:33 PM

CR,
You list professor of Chemistry and physics in your profile...
if that is true...
you should be telling us what would work the best...

but I am interested in why you do not trust what was used for multi decades with no complaints for R12.... since you are staying with R12... ?

Putting in some kind of combo oil would not take away the need to do a full flush when changing refrigerants in my opinion. That oil , while it may work fine with both, would be saturated with whichever it was used with first... no way that I know of to clean it inside the system... and you do not want to cross contaminate any of your equipment.

Are you really a professor of Chemistry and physics ?

Cr from Texas · #10 03-15-2009, 11:12 PM

Yes,
I really am a professor of chemistry and physics. But 35 years of experience in chemistry (my specialty is surfactants, not lubricating oils) has taught me that we often overlook some of the variables in laboratory testing. Field tests and the data produced in actual use has proven many theory to be lacking in not considering all of the variables.

From a chemical perspective, both the mineral oil and the ester oil should be relatively inert. But we have learned from engine oils that the synthetic holds a clear advantage. What I don't know and mentioned above is the experience of how much refrigerant is retained in the oil upon evacuation - should be almost zero. I also have not been able to find an adequate revelation of the chemical composition of the FrigiQuiet oil. Especially the nature of the molecule ends. Capped PAG oils have a strong theoretical advange over regular PAG as the capping limits reactivity. Ester oils have functional groups that may also need capping and this is not revealed in any of the technical information easily available on those oils.

I'll probably go with the synthetic. If I ever need to change refrigerants, I'll do a flush but I'll worry less about residual incompatible oil.

ah-kay · #11 03-16-2009, 02:03 AM

Quote:

Originally Posted by Cr from Texas

Yes,
I really am a professor of chemistry and physics. But 35 years of experience in chemistry (my specialty is surfactants, not lubricating oils) has taught me that we often overlook some of the variables in laboratory testing. Field tests and the data produced in actual use has proven many theory to be lacking in not considering all of the variables.

If you are really a professor or a respected educator, then you should convert your car to R134A and do not hoard R12. It is unethical to be still using R12 as it is ozone depleting.

LNGfish · #12 03-16-2009, 07:58 AM

He wouldn't be hording R-12 if he shared some with me right? , lol.

Professor, lets do an experiment. Since my system has Ester 100 and 134A let's have you send me some R-12 and we can see how much colder it gets. lol.

Graplr · #13 03-16-2009, 09:53 AM

Quote:

Originally Posted by ah-kay

If you are really a professor or a respected educator, then you should convert your car to R134A and do not hoard R12. It is unethical to be still using R12 as it is ozone depleting.

You're reasoning is backwards. The R12 he is using is already made. If he were to specifically create NEW R12 to use than there may be a problem. Recycling and safely using an old product is more 'eco-friendly' than using a product that has to be manufactured.

Look at it this way. The R12 is already there. Would you rather have someone else get the R12 and dump it into the atmosphere or place it in the hands of someone who will use it responsibly ensuring that it is not vented to the atmosphere. The cans of R134a are being made to be purchased. We could save the energy and pollution going into the production of a new product by using the old.

I use the BVA100 from ackits with my R12. I've only run it one season but it works fine.

Matt L · #14 03-16-2009, 10:14 AM

Quote:

Originally Posted by Cr from Texas

Thanks for are the replies. Looks like I'll be able to stick with R-12 for a long time. I just located (via Craig's list) and purchased today, 2 partial drums of R-12. One weighs a total of 28 lbs and the other 21 lbs. Anyone know about what an empty cyliner weighs?

I have a 30lb cylinder here that is stamped TW 15.8#.

Cr from Texas · #15 03-16-2009, 11:08 AM

Quote:

Originally Posted by Matt L

I have a 30lb cylinder here that is stamped TW 15.8#.

If that's the case, I didn't get quite as good of a deal as I thought.

I'm looking further into the chemistry but information is very limited. Looks like the FrigiQuiet is probably a bicapped PAG and the BVA Auto 100 is probably a POE type.

Graplr - You are right on target. Once a product is produced, it either gets into the environment eventually or must be destroyed (sometimes at greater risk to the environment). The flaw in the reasoning of many environmentalists is not looking at the full life cycle of products. 134a is likely on the way out also.