bojan

I wondered how hard it would be to recharge the system on my own. It seems to be working properly, so it probably only needs some more freon. Has anyone ever done this, and would it be necessary to do the r134 conversion on a 200 and how hard is it? Also, if anyone has a detailed explanation, please share the info.

Will Ng

stick with R12. It's more efficient, and probably cheaper than converting to R134a.
Since your system is operational, it probably doesn't have any major leakage issues.

If you have a NipponDenso compressor, you should be able to port the system to R134a. BUT, this requires extensive mods to be considered a CORRECT procedure.
Some hoses will need to be replaced, new O-rings, new orifice valve(?), complete flush of system to remove R12 oil, new drier.
R134a will not be as cool as R12 regardless what people claim. System pressures and condenser capacity was designed for R12.

jimweisptd

I've been using Freeze-12 with success.
85 5000T
81 Corvette

Tom Serrago

with ND and Zexel compressors to R134A at the customers request and expense.
A kit is still available at some dealers for $295.
and consists of all hose connection O rings, manifold gasket, restrictor, compressor O rings, shaft seal, PAG oil, 134A service valve adaptors & new labels, and a new accumulator. No other components are changed unless damaged. You can buy the same parts for less than half the $, if you do some looking around.

How well it works afterwards is totally dependent on the condition of the system beforehand, and how well it was prepared and cleaned/flushed prior to the conversion.

I'm pulling vent temps in the low to mid 40's with the conversion in the 85 5KS,
the 99.5 A4 does not do any better with it's factory system.

comp_jas

I guess since you say its working properly the output is not as cool as it used to be.

You can't buy R-12 to top it off unless you (or a friend)have an EPA HVAC certicification. You can take an online test at the EPA website to achieve cert for $20. You'll have to sign a bunch of papers stating what you are using the R-12 for. Kinda scary since if you claim mobile refrigeration you need to have recovery tanks etc.

If you're not willing to go the R-12 route, you have to convert to R-134. I did not do the correct procedure other than pull a vacuum on the system and the conversion has worked fine.

Whichever route you decide the forum can provide the necessary info.

maca

hy to all,
when you chance from R12 to R134a you have to change all (!) gaskets and o-rings. R134a needs a syntetic PAG cooling oil whitch doen`t fit to the old one mineral oil used with R12. also the old o-rings are not resistant against the new oil. so the compressor will broken down soon.
but to change to R401 or R413 this is an option too. in this case you can use the same cooling oil and you don`t have to change al o-rings. greetings arthur

rooster 2

Oil used to be the reason, not so now. In the beginning R-134A used PAG oil as its lubricant. It would not mix with R-12 oil. Now, R-134A is available with Ester oil as its lubricant, which mixes better with R-12 oil.

Interdynamics Company sells kits at Wal-mart and Autozone for about $35 to retrofit an R-12 system to R-134A. Their directions say to vacuum out all R-12 and its oil, then add their kit of R134-A and ester oil. In their directions, they hint that the contents of their kit can be added to the residual of R-12 and oil. I really took that to mean that you could just add their product to whatever R-12 and oil are still in the system. I have done this with fair success. Got two systems to cool okay, but not great.

In another case, I just added one can of Interdynamics containing a mixture of 12 oz. of 134-A refrigerant charge, with 3 oz. ester oil charge, with leak sealer to my daughter's '92 R-12 system. The can cost about $15. This can came with its own hose for A/C low pressure side attachment. The result was very good. It produced great cold air through a system that was acting like it was just a can short of being fully charged. I did not change any components in the system. The system has held this charge very well.
Regards, Rooster