Before recharging a dead system with ANYTHING a good shop will find and repair any leaks. In fact it is the law. On the subject of converting to R-134A, early on there were not many good "drop-in" replacements so a lot of shops tried to convert the older R-12 systems over to -134. There are a lot of mixed results. Some systems seem to tolerate the conversion better than others. A lot depends on the compressor, the kind of oil, and how contaminated the system is at the time of conversion. The -134 definately makes the compressor run harder (higher head pressures) and there is some loss of cooling capacity because the sizing of the coils is smaller for -12 which is more effecient than -134. The horror stories of the oil turning into gunk does not seem to be the general case (unless the system is heavily contaminated). My opinion is that with several good drop-in replacements available now for R-12 there is no reason to lose capacity switching to -134. I do strongly recomend ALL leaks be fixed, the system flushed, the service valves be replaced, and the oil changed. The system should then be completely evacuated to 700 microns for an hour before being recharged. R-12 can still be obtained. It is expensive but not so expensive as to be prohibitive. The bigger cost in doing A/C work is still the labor. You only need about 2 1/2 lbs of the stuff so at $60 a lb you are only talking about $150 for the refrigerent. BTW any good, competant shop can find leaks. Generally if it is difficult to find a leak it is usually the evaporator coil. The more common areas of leakage are the service valves and/or the discharge hose. I like leak-test solution, aka soapy water. It doesn't stain or cause a mess, works with the fans running, and doesn't give false positives. It also provides positive indication of the location AND the amount of leak. David Teitelbaum vin 10757 --- In dmcnews@xxxxxxxxxxxxxxx, Soma576@... wrote: > > Nathan, > > I have done a cheap-o conversion to R134A with mixed results. Basically I > just had the system sucked down for about an hour, then ports changed and > reinstalling with 134A and compatible oil. Didn't take the compressor apart or > replace any O-rings or anything. It blows nice and cold when it is fully > charged, but I need to get it recharged every year or two because apparently too > To address comments privately to the moderating team, please address: moderators@xxxxxxxxxxx For more info on the list, tech articles, cars for sale see www.dmcnews.com To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnews Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/dmcnews/ <*> To unsubscribe from this group, send an email to: dmcnews-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/