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A/C question #785891 08/27/10 08:48 PM 08/27/10 08:48 PM
Joined: Mar 2007 Posts: 698 Hilliard, Ohio GKMOPAR OP mopar
GKMOPAR OP mopar Joined: Mar 2007 Posts: 698 Hilliard, Ohio	How do I check for a leak in an a/c system? I have a 1970 Challenger that I have replaced all the orings in and I still can't get to hold a vacuum. I am going to recharge it with R12 but need to find the leak. I know there is uv dye systems but I think this is for a134 and the system needs to be charged to check. Is there a way to find a leak without freon in the system? I have a vacuum pump to evacuate the system.

Re: A/C question [Re: GKMOPAR] #785892 08/27/10 09:24 PM 08/27/10 09:24 PM
Joined: Jan 2008 Posts: 2,592 None 71rm23 master
71rm23 master Joined: Jan 2008 Posts: 2,592 None	Both systems need to have freon in them. Otherwise, theres no way of determining where the leak is at without pressure in the system. Dyes are available for both. I also have used a "sniffer" which detects freon leaks at any place where leaks can occur. Such as at the compressor, lines, drier, etc. Hope this helps.

Re: A/C question [Re: 71rm23] #785893 08/27/10 10:27 PM 08/27/10 10:27 PM
Joined: Feb 2005 Posts: 710 St Louis, MO 63026 convx4 super stock
convx4 super stock Joined: Feb 2005 Posts: 710 St Louis, MO 63026	Use compressed air to blow a LITTLE air presser in to the system and listen for a leak.

Re: A/C question [Re: convx4] #785894 08/27/10 10:36 PM 08/27/10 10:36 PM
Joined: Jul 2010 Posts: 40 Corona CA wyotech_cuda440 member
wyotech_cuda440 member Joined: Jul 2010 Posts: 40 Corona CA	Don't use compressed air, you need to keep the system clean and dry. You can fully charge it with r12 and then leak check, but r12 is pretty pricey. Instead, put an ounce or two of r12, and then pressurize it with nitrogen. Then you can use a sniffer to find the leak. Daily driver: 2002 Dakota R/T, slightly modded Weekend machine: 70 cuda, 440-6 street/strip

Re: A/C question [Re: wyotech_cuda440] #785895 08/27/10 10:40 PM 08/27/10 10:40 PM
Joined: Apr 2007 Posts: 905 SD Z zrxkawboy super stock
zrxkawboy super stock Z Joined: Apr 2007 Posts: 905 SD	Quote: Don't use compressed air, you need to keep the system clean and dry. ditto! It's Swifty! Swifty, you toad sucker!

Re: A/C question [Re: zrxkawboy] #785896 08/27/10 11:41 PM 08/27/10 11:41 PM
Joined: Feb 2003 Posts: 8,717 A Andrewh master
Andrewh master A Joined: Feb 2003 Posts: 8,717	well you could try smoke. set the vacuum pump up and blow smoke around and see if you can see where it is being sucked up.

Re: A/C question [Re: wyotech_cuda440] #785897 08/28/10 12:33 AM 08/28/10 12:33 AM
Joined: Nov 2003 Posts: 36,041 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,041 Lincoln Nebraska	Quote: put an ounce or two of r12, and then pressurize it with nitrogen. Then you can use a sniffer to find the leak. More info on this please as I'm adding A/C to my 65 Dart (OE stuff w an under dash evap). First exp ever w A/C live every 24 hour block of time like it's your last day on earth

Re: A/C question [Re: RapidRobert] #785898 08/28/10 01:41 AM 08/28/10 01:41 AM
Joined: Jul 2010 Posts: 40 Corona CA wyotech_cuda440 member
wyotech_cuda440 member Joined: Jul 2010 Posts: 40 Corona CA	Quote: Quote: put an ounce or two of r12, and then pressurize it with nitrogen. Then you can use a sniffer to find the leak. More info on this please as I'm adding A/C to my 65 Dart (OE stuff w an under dash evap). First exp ever w A/C Here's an article explaining it a bit, http://www.aircondition.com/tech/ If you are doing this yourself, you will need some freon, r22 or r12 for the test. r22 is cheaper, but you will need some r12 for the final charge anyway. Either type of freon will require an EPA liscense to purchase. You will need a tank of nitrogen, it's available at welding supply stores like Airgas, and you will also need a regulator for the nitrogen tank, plus you will also have to make up a hose that will connect to the regulator and the flare fitting on your car's a/c system. If you dont have a/c experience or liscenses, you should install the system, then take it to a shop for leak tests and charging. Daily driver: 2002 Dakota R/T, slightly modded Weekend machine: 70 cuda, 440-6 street/strip

Re: A/C question [Re: wyotech_cuda440] #785899 08/28/10 02:00 AM 08/28/10 02:00 AM
Joined: Nov 2003 Posts: 36,041 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,041 Lincoln Nebraska	thank you, I will stay on it live every 24 hour block of time like it's your last day on earth

Re: A/C question [Re: RapidRobert] #785900 08/28/10 11:17 AM 08/28/10 11:17 AM
Joined: Jan 2003 Posts: 21,088 Niles , Ohio T therocks oh wait.but hey.lets see.oh yeah.
therocks oh wait.but hey.lets see.oh yeah. T Joined: Jan 2003 Posts: 21,088 Niles , Ohio	Just convert to 134.Its easy and cheap.A lot of shops dont even have equipment for 12 anymore.That and you have to be real careful with any 12 you buy now.If its old stuff its OK.The newer 12 from offshore had some dangerous gases added to it.Some of the substitutes also had stuff like benzyne etc in it.Dye is probally the best to find a leak.It really shows up under a black light.We had sniffer and black light at the shop.99 % of the time I used the light.Also check the vacuum gauge/I had one that would leak down after a bit.I always pulled a vacuum and saw if it held for 15 minutes.Rocky Chrysler Firepower

Re: A/C question [Re: therocks] #785901 08/28/10 11:13 PM 08/28/10 11:13 PM
Joined: Feb 2005 Posts: 710 St Louis, MO 63026 convx4 super stock
convx4 super stock Joined: Feb 2005 Posts: 710 St Louis, MO 63026	There is a proper way that a ac shop will preform the work, he was not asking how they do it. My advice was from a back yard repair guy giving advice to another back yard repair guy. If he has a system that has a leak, it is already contaminated. Using the vacuum to suck smoke in to the leak is also adding contamination in to the system. So using compressed air to find a leak isn't to far fetched for a back yard mechanic.Why waist the money and time with all that fancy stuff, use what you got.

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