I have a 1990 740 GL that is ready to be retrofitted to r-134. I've read the FAQ's on it and searched the old posts.
I have read the procedures as extensive as they are, but with the new retrofit kits using PAG oil, is it completely necessary to replace the receiver/ drier and drain the compressor.
I'm also familiar with the problems of old retrofits that did produce bad chemical reactions.
I've done and heard of these switch overs being done successfully by evacuating the system and simply recharging the system.
Is there something unique to the ac system in this volvo that requires so much more to be done?
Thanks,
-Brent
guysaab@msn.com

See my post on the subject "Where You Buying Your A/C Conversion Kit? 𖘴]" You don't have to go to R-134a or make any expensive conversions. Ther is another option which is better, cheaper, and legal.

My 760 AC clutch burned out last summer. Looking for a cheap but effective solution,
I investigated using a hydrocarbon AC replacement for R12. By that I mean a custom mixture of propane and butane. I figure the worse that I could do is trash the compressor, or go up in flames.

The Research from knowledgable sources indicates that hydrocarbon based refrigerants are LEGAL (you can replace 134 with hydrocarbon) and experience from millions of users in other countries show that noone has been BBQ'd (yet).

The system blows COLD - between 30 and 40 degrees at the vent.
So, should I keep driving in my nomex underwear, or is this a reasonable idea?

I would appreciate any feedback from others with experience or advice.

I did my wife's 91/740 2 summers ago. I did change out the evaporator and drained the compressor of all oil. I hooked up a vacuum pump prior to charging the system and the car blows out snowflakes on a blistering Texas summer day. Not hard to do and the results are good. Good luck!

Henry

92/940-224k, 97/850-77k, 91/740-179k (just sold it to my brother about a month ago)

Two years ago I asked a dealer to give me an estimate for the conversion... $1200! So an indi did it for me for $250. Dealer was going to replace "everything." Said it wouldn't work right otherwise.
My converted system works just fine, thank you very much. Don't scrimp on the little stuff, you will be better off next year.

Klaus
--
95 854T, 88 780, 88 245

You need to replace the filter dryer as a sauturated or degraded one will not remove contaminants, thereby allowing acids to form and degrade the compressor seals. RD's are cheaper than compressors.

At least you need to thoroughly drain the mineral oil from the compressor and replace with PAG oil; although I believe that Ester is preferred for retrofits.

I don't think there is anything unique about Volvos that requires "so much more". The receiver drier should be replaced any time the system is opened or refrigerant is changed/converted. They are typically specific to one type of refrigerant. I 'converted' my 1991 740 from 12 to 134 by swapping the receiver drier, oil, and refrigerant. The non-barrier hoses did not hold up and the system just did not get cool enough (black wagon) on hot summer days. The next year, I replaced the condensor, compressor, expansion valve, hoses, etc, etc w/ 134 specific items. Now I get 43F air temp on the highway. Yesterday, I converted an old BMW (1988 528e) by just doing the R/D, oil and refrigerant. We'll see how long it lasts...