R134q Refrigerant?

[gatorcruz]

I was going to charge the dash AC with R134A and noticed that it said it has R134q. I have never heard of it and couldn't find anything on the internet about it. Does anyone know the difference?

Thanks.

[TXiceman]

It is usually written with a small a, R-134a. I have never heard of R134q. I did a search and found a few obscure references to it...nothing to do with air conditioning.

Make sure you are not miss reading a lower case "a" that was not printed or stamped properly.

A 1996 should have had R-134a from the factory. If there was a conversion done on it, some one could have stamped a tag with a "q" just to make you come back to them for any work.

Ken

[gatorcruz]

Ken,

I have been thinking the same thing... that maybe it is a lower case "a" and that the upper "`" has faded off. Just want to be sure before I charge it.


Thanks.

JC

[RVDude]

You have it right. In auto use there is only R12 (gone) and R134a. Now, R134a comes in many different brands (Suva, Forane, etc...) but R134a is R134a. That q is a typo of some sort. Filler' up, you got it right! Note that R134a charge fittings differ from R12 fittings so you can't mix them up... even though the new 134a stuff mixes far better with the old oils, seals, and R12 than ever.

[TXiceman]

RVDude, R-134a does not use mineral oils as did the older R-12. The new oils are PAG and POE synthetic oils and require different elastomers. Put R-134a and the new oils in an old system, you need to change o-rings, replace hoses and flush all of the older oil out of the system. The synthetic oils do not mix well with the old mineral oils.

Some of the "quick and dirty" shops will short cut and not do a proper conversion, which will work for a short time and then you will develop problems. When an R-12 system is converted to R-134a, special adapters for the hose connections are locked on the old R-12 connection so that you will know that R-12 is not in the system.

Ken

[Jocat54]

Quote:

Originally Posted by TXiceman RVDude, R-134a does not use mineral oils as did the older R-12. The new oils are PAG and POE synthetic oils and require different elastomers. Put R-134a and the new oils in an old system, you need to change o-rings, replace hoses and flush all of the older oil out of the system. The synthetic oils do not mix well with the old mineral oils. Some of the "quick and dirty" shops will short cut and not do a proper conversion, which will work for a short time and then you will develop problems. When an R-12 system is converted to R-134a, special adapters for the hose connections are locked on the old R-12 connection so that you will know that R-12 is not in the system. Ken

Ken I agree with all you said, but I have done the "quick and dirty" and it is still working after approx. 5 years. (my own old work truck) Does show signs of hoses leaking now.

Just my 2 cents.


John

[TXiceman]

For a couple of years before the manufacturers made the conversion to R-134a they were replacing the hoses and elastomers with the newer materials. So you may well have the materials required for R-134a.

I have been in the industrial refrigeration business since 1970.

Ken

[RVDude]

TX maybe you know the answer to this. I know that the original 134a and oil formulations of the 1990's were relatively destructive when used in improperly retrofitted R12 systems. However, I thought in the 2000's both 134a and its compatible oils were significantly improved to be substantially less destructive when installed in an impure R12 system. I also thought 134a physical performance as a refrigerant had also been improved in these newer formulations and better mimicked the wonderful refrigerant properties of R12. I can recall reading newer 134a retro-kits that said to basically ("properly dispose of") the R12, drain as much oil as possible and just refill with the 134a and oil - no other mods required. Did I misunderstand something?

[TXiceman]

The R-134a is the same, no changes in the thermophysical properties. What has been done is to improve the system performance by optimizing the equipment design for the new refrigerants. The PAG and POE oils are the same and are required due to R-134a not being a chlorine based refrigerant.

As time progresses, the manufacturers decided it may not be necessary to do such a through flush and you can get by in 90% of the cases. You will find the occasional swap that can give problems.

Part of the problem is the oil manufacturers all using slightly different oil additive packages. One may not be compatible with another and you can get excessive oil foaming and even polymerization of the oil.

On a small system like in a auto, you can take the chance and maybe not have any damage. On a larger system where the compressor can cost in excess of $20,000 and up to $150,000 and up (just the compressor), you do not take chances. I have had customers change from a mineral oil to a synthetic oil or just to change brands, suddenly start to have oil system problems. An oil analysis will quickly detect the problem. And they wound up dumping all of the oil, some 200 gallons(or more) at a cost of $25.00 per gallon, flushing the system and recharging the oil. So $15,000 later plus labor and about 3 days of down time they were ready to restart.

In an auto engine, you do not have to worry too much about mixing brand A with B, but in an expensive compressor with a refrigerant and special oil, it can be a real concern.

There are numerous articles on the internet about oil swaping and you have to sift through them and find out which ones are real. The best source of information is the refrigerant manufacturers.

Rather than swap an older R-12 auto systems to R-134a, my recomendation is to use one of the blended drop in replacements. One trade Name is "Hot Shot" and there are many others. These readily use the standard mineral oil and the swap is easy.

The whole purpose is to just not loose your cool.

Ken

[RVDude]

Thanks for that thorough answer! (and the prior one too)!!!!!!!!!!!!!!!
It 'splains a lot!!!!!!!!!!!!!!!!!!!

[snl2106]

R134a uses what they call PAG oil, you can however use Ester oil. It will mix fine with the factory oil (pag) with no harmful results. We use it here in my shop and have never had any situations.