I did not mention R-134 because I do not recomend converting. As long as you can still get R-12 it is the best to use since the system was DESIGNED for it's pressures. Any other refrigerent will not work as well. If you can't (or won't) use R-12 there are drop-in replacements that can proform almost as well as R-12 (and better than R-134). As for pulling vacuum, you cannot read low vacuum in inches. You have to go to other, more sensitive scales. I use microns. You can actually measure the amount of moisture with it. I say pull a hard vacuum for an hour. If you have a micron gauge you run the vacuum till you see it drop down and stay down for a while. That means all of the moisture has vaporized. You should also turn the compressor by hand during the evacuation process to lubricate the seal and expose all the chambers inside to the vacuum. I have seen the consquences of running a system with too much moisture. It will last a lot longer if you get the moisture out. In fact with a hard vacuum you can pull the residual moisture out of the dryer so it doesn't have to be changed if the system is not contaminated. I do not expect to change your mind on this but can only point out the "correct" way to work on A/C systems. A good vacuum pump IS expensive, that is why I recomend owners go to a good A/C shop with a reputation for quality work. It may be expensive but if it is done right you won't be going back every year. On Deloreans we are kind of "lucky" that it is a rather generic system that just about any well equiped A/C shop can service. The only special tools are to rebuild the compressor and most shops will just change it if there is a problem anyway. Using the engine to "vacuum" the system won't even get all the air out let alone remove much moisture. David Teitelbaum vin 10757 --- In dmcnews@xxxxxxxxxxxxxxx, "content22207" <brobertson@xxxx> wrote: > As the owner of several A/C systems that work perfectly, and which I > 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/