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Tim Hancock Tim Hancock is online now
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Join Date: May 2004
Posts: 10,818
Quote:
Originally Posted by A930Rocket View Post
Yes, I'm going to pump/evacuate it with gauges before hand.

I was just thinking that a pressure test with maybe some soapy water might be an option to find leaks. They guys do it on the homes to determine if it leaks.

Especially with the coolant/freon costing so much.
I just pressurized my 911SC yesterday to find a slow leak.

I got my old stock AC working and switched to 134 about 4-5 years ago on my SC by pressurizing the system with air and then spraying everything with soapy water (I simply dump about an ounce of dish soap in a spray bottle filled wih water) to find the leak (AC line by the jack port was damaged by the PO and was the source of the leak). I fixed the leaking hose, then installed a new drier then evacuated the system with a vacuum pump prior to charging with some oil and 134. It has worked great for the past several years needing only a can of 134 each spring. This spring it no longer worked and after hooking my gages up it read only 10psi prior to running so I knew I had a leak to fix again. Isprayed everything down and found no visible bubbling leaks so I reluctantly pressurized with compressed air to about 40psi..... still no visible leaks..... I pressurized to 70 psi and resprayed eveything and low and behold my 4-5 year old drier had a leak that showed up by bubbling the soapy water solution.

I just bought a new drier and after installing, I will put the vacuum pump on it for a couple hours then recharge with 134 just like I did 4-5 years ago and all will be well again.

While pressuring with air seems like bad idea, if you have a system that completely leaked out, it will have been exposed to air anyhow. So long as you vacuum the system for a long time to boil off the moisture, it will be fine. I am fairly confident I would not have found this latest leak using only the -14 psi that a vacuum produces.
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Last edited by Tim Hancock; 06-03-2011 at 06:12 PM..
Old 06-03-2011, 06:10 PM
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