AC R134a conversion

Recently I had my AC system converted to run on R134a instead of the original R12.

I have changed the Accumulator and compressor with new units (the old one died from unknown causes).

Problem is: does any of you know the correct quantity for a R134a recharge (refrigerant + oil) after the conversion?

Right now it seems that it doesn't cool as much as the R12 did and I wonder what might be the cause to this..

systems using R134 are reputed to be a little under the R12 performance...so what you experience might be the new normality.

http://www.patentstorm.us/patents/6056891/description.html Nearly all pre-1994 cars
that were retrofitted from R-12 to R-134a refrigerant systems have had
cooling performance problems. The 1994 and later model year cars were
manufactured with R-134a refrigerant systems, in general. Some have
performed well, and some have not. R-12 refrigeration systems used
500-viscosity mineral oil as a compressor lubricant. R-134a does not
dissolve in (is not miscible with) mineral oil, so the mineral oil will
not return to the compressor properly. New refrigeration systems
lubricants were developed for R-134a, which were primarily polyalkylene
glycol (PAG) based oils and polyol ester (POE) oils. The bulk of 1999
model year cars contain PAG oils. Chlorinated refrigerants, such as R-406A
(R-600a/R-22/R-142b (4/55/41)) (see also U.S. Pat. No. 5,151,207) or R-12, cannot be directly used in systems that use PAG oils as almost all PAG
oils are destroyed by chlorinated refrigerants. Only nonchlorinated
components may be used in creating an R-134a substitute to avoid
destruction of the PAG oil. However, a recently developed PAG oil, brand
name Daphne.RTM. of Idemitsu Kosan Kabushiki, Tokyo, Japan (also known as
"double end capped PAG oil"), has claimed to be able to tolerate chlorides
and has even claimed to be able to run in R-12 systems without breakdown.
This oil is not in widespread use at this time. Millions of cars have been
and continue to be manufactured using the original, chloride sensitive PAG
oils.

One option to improve the performance of a poorly performing R-134a
refrigerant system is to painstakingly remove all the PAG oil by
disassembling and flushing the system, including the compressor. Mineral
oil can then be charged into the system along with R-406A, R-12 or any
other blend refrigerant that offers a performance improvement over the
performance of R-134a. This process is very labor intensive.
Another (http://www.eurocarparts.com/forum/post.asp?method=ReplyQuote&REPLY_ID=18957&TOPIC_ID=6123&FORUM_ID=43) option maybe. 416 gas?.

I have a 1990 Pontiac Transport with AC. Fixed Orifice System . R12 Set up. 3 years ago I tested the system for leaks and found none - vacuumed the system for 45 minutes. Put in 6 ozs of mineral refrigerant oil and just over a Kilo of RS24 refrigerant.

The AC system is still working perfectly with an air outlet temp of 6c.

The RS24 refrigerant has to be charged as a liquid ( bottle upside down) into the low side using a restrictor device which converts the liquid into gas. Rs24 should never be charged as a vapour as the mixtures of different refrigerants will enter the system at different rates.

Total cost £65.00. I can recommend this refrigerant to anyone with an old pre-1992 vehicle who does not want to go the expense of converting to R134a. Not all old compressors like running on PAG lubricants after years of mineral oil.

Ivanhoe
Also maybe duracool r12a (http://www.google.ca/search?q=duracool+r12a&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a). http://www.accesscnc.com/catalog.html
or
http://tinyurl.com/6mbn66
http://tinyurl.com/5vbawh
http://tinyurl.com/5cqgjs

(http://tinyurl.com/6mbn66)