Andy, The molecules of R134 are smaller than R12 which is like antifreeze is smaller than water so that's why you may have an accelerated leak. Then when you add the dye don't clean the engine or the AC system or it will wash away. If you were starting from an empty system then I would add about 2.25 lb's and start from there, but since you have a working system I would let the gauges under load or test tell what you need. Be careful on adding oil as to not wind up with to much in the system. John Hervey www.deloreanautoparts.com Your complete new AC system supplier. -----Original Message----- From: dmcnews@xxxxxxxxxxxxxxx [mailto:dmcnews@xxxxxxxxxxxxxxx] On Behalf Of Soma576@xxxxxxx Sent: Thursday, March 15, 2007 7:19 PM To: dmcnews@xxxxxxxxxxxxxxx Subject: [DML] A/C - switch back to R12? Hey Group, It has been a totally uneventful winter for my DeLorean - for once! All I did last fall was wash and detail it, clean the interior, put clear plastic seat covers over the seats, fill the tank up and add Sta-Bil, then fill the tires up to 44 PSI. I covered the car and pulled the battery out. Once a month I trickle charged the battery overnight. It has sat since October. Now yesterday I just reinstalled the battery, turned the key, and after one second of cranking it fired up and settled into a beautiful idle just like usual. Ah, it is so nice having a car that is tuned up and reliable! One part of my yearly ritual seems to be evacuating and recharging the A/C. When I bought my D in 2000, the previous owner suggested the A/C needed to be topped off. I refilled with R12 until later that summer, when the freon hose near the steering column blew out from rubbing the universal joints. At that point I had the hose cut out and replaced, and the system was sucked down and switched to R134A. At this time there was some suggestion that the main lines may be seeping freon but I did not replace them. I figured if I spent $100 a year to recharge it, so be it until I rebuild the whole system. My question now is this: Every year I have the shop check for leaks (they add dye every time) and they can't find any. I think the R134 is seeping out faster than R12 would. Should I have the system sucked down and re-converted to R12 even though I know it will be more expensive? I was so-so on the cooling power of the A/C last year. It seems to be losing efficiency, or it wasn't charged properly last time. If I go with R134a again, what is the proper fill, lb-wise? I know it is supposed to be different than R12. My receipt from the last service says 1.75lbs. Thanks for the input - Andy Fargo, ND 1982 DeLorean DMC12 VIN 11596 ************************************** AOL now offers free email to everyone. Find out more about what's free from AOL at http://www.aol.com. [Non-text portions of this message have been removed] 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 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/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/dmcnews/join (Yahoo! ID required) <*> To change settings via email: mailto:dmcnews-digest@xxxxxxxxxxxxxxx mailto:dmcnews-fullfeatured@xxxxxxxxxxxxxxx <*> 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/