Automotive A/C refrigeration oil

[WyrTwister]

Planning on retrofitting a 1991 Caprice 5.0L A/C system with R-134A .

I think I will need PAG oil ? Which type / viscosity ?

Thanks ,
Wyr
God bless

 

[FowVay]

R-134 systems use PAG oil (Polyalkylene glycol). This is the only oil that should be used in a R-134 system that came on a vehicle.

If you're doing a retro fit then I believe they use a ester based oil that is compatible with both mineral oil from the R-12 system and PAG oil from the 134 system.

So I'd guess you need the ester oil for a retro-fit. The component supplier should have given you a instruction sheet regarding this.

 

[bullwinkle]

POE oil is what you want-you'll need to (preferably) recover the old refrigerant, remove your compressor and dryer/accumulator, drain the oil out of them into a clean container, measure exactly what you took out & add that amount of POE oil into your compressor, replace the dryer, all o-rings, and expansion valve/orifice tube with parts that are R-134A compatible, and add the R-134A adapter fittings onto your existing fittings, pull a vacuum, & recharge the system. And be prepared to lose up to 30% of your A/C capacity in the process. That's why I put R-12 back in the old cars, too much work to change them over for uncertain results!

 

[Chris142]

You want ester100 when doing a retrofit to r134a. Pag oils do not play well with any chlorination that's left in The system from R12.

 

[Chris142]

Bullwinkle: with all due respect you are a little shy on the oil amount
Spec is 3.5oz per lb of r134a. So if dealing with a 2lb system it needs 7oz of oil. I would replace the R12 white orifice tube with a yellow or maybe a orange one for better cooling with r134a

 

[artificialist]

Originally Posted By: bullwinkle
POE oil is what you want-you'll need to (preferably) recover the old refrigerant, remove your compressor and dryer/accumulator, drain the oil out of them into a clean container, measure exactly what you took out & add that amount of POE oil into your compressor, replace the dryer, all o-rings, and expansion valve/orifice tube with parts that are R-134A compatible, and add the R-134A adapter fittings onto your existing fittings, pull a vacuum, & recharge the system. And be prepared to lose up to 30% of your A/C capacity in the process. That's why I put R-12 back in the old cars, too much work to change them over for uncertain results!

This is why my friends either recommend also getting an updated condenser or buying something like "Freeze12" Which is a blend of different refrigerants.

Where I am, R-12 is next to impossible to find, and nobody has the tools for it anyway.

 

[WyrTwister]

Originally Posted By: Chris142
Bullwinkle: with all due respect you are a little shy on the oil amount
Spec is 3.5oz per lb of r134a. So if dealing with a 2lb system it needs 7oz of oil. I would replace the R12 white orifice tube with a yellow or maybe a orange one for better cooling with r134a


Please explain to me about the different " colors " of orifice tubes ?

This Caprice has been in storage for 10 - 15 years . During that time , the oil and fean leaked out at the compressor shaft seal . Car has 40,000 + origination miles .

The compressor did not thrash , sending metal through the system and stopping up the orifice tube . Therefore , I had not planned on replacing it .

God bless
Wyr

 

[WyrTwister]

I ended up replacing the seal , the accumulator and the o-rings where the lines mate to the compressor .

I used ester 100 oil with UV dye .

Thanks ,
Wyr
God bless

 

[Colt45ws]

Originally Posted By: WyrTwister
Originally Posted By: Chris142
Bullwinkle: with all due respect you are a little shy on the oil amount
Spec is 3.5oz per lb of r134a. So if dealing with a 2lb system it needs 7oz of oil. I would replace the R12 white orifice tube with a yellow or maybe a orange one for better cooling with r134a


Please explain to me about the different " colors " of orifice tubes ?

This Caprice has been in storage for 10 - 15 years . During that time , the oil and fean leaked out at the compressor shaft seal . Car has 40,000 + origination miles .

The compressor did not thrash , sending metal through the system and stopping up the orifice tube . Therefore , I had not planned on replacing it .

God bless
Wyr

The colors indicate the size of the orifice. White is .072 Yellow is .062 and orange is .057.

 

[babyivan]

Originally Posted By: bullwinkle
That's why I put R-12 back in the old cars, too much work to change them over for uncertain results!


Where do you find the old R12? I long for the days of old!

My compressor grenaded the other day thanx to the PO doing a half-a$$ R134 conversion

I probably wouldn't be able to go back to the old stuff at this point, just curious as to where you can get R12 from.

I'm probably gonna "sweat it out", due to the fact that it will probably cost me at least $500 to get my A/C back up working.

To the OP, if you can find R12, then that would be the easiest way to go of course.

If not, then change the dryer for sure, orifice tube filter, and possibly the condenser(depends on contamination), also I believe a new condenser will improve cooling... at least it did for me on a '93 Regal. Clean the system out really good (I read about using brake cleaner), replace with PAG oil (don't know how much) and then R134, 80% of what your car is rated for with R12. This is what was told to me that needed to be done with my car ('87 Ciera). I need a new compressor as well due to mine spewing its guts.

I don't know about Esther oil or the other oil that was mentioned, this is the first time I heard about this.

 

[1 FMF]

http://www.autoactech.com/issues.htm
http://www.technicalchemical.com/techsupport/lubricantguide4.pdf

There's ISO 46, 100, or 150 for PAG, you should use the viscosity specified by the AC compressor manufacturer.
PAG is the preferred oil, the esters are more marketing hype than anything. If you're doing a conversion and the system is flushed, then you're not mixing with mineral oil left over from the R12 charge so you don't need ester oil.

 

[DBMaster]

I have three cans of R-12 that were purchased from an automotive parts place in Mexico about five years ago. Does anyone want them? The system in my 89 Accord used to lose about 1/3 of a can per year so I kept it around to top off. When the second compressor died in 2010 I went with Freeze 12. It is 80% R134a and 20% R142b. The performance was good (43 vent temp v. 40 with R-12). It also works with the same oil that worked with R-12. I found that it also did not leak that 1/3 can per year, but I got rid of the car two years after the compressor/refrigerant conversion.

I would call Freeze 12 a good sub for R-12. It runs at similar pressures, too.

 

[jrustles]

Originally Posted By: WyrTwister
I ended up replacing the seal , the accumulator and the o-rings where the lines mate to the compressor .

I used ester 100 oil with UV dye .

Thanks ,
Wyr
God bless


Exactly the oil you needed. Good job.