Locating AC leak

[joshuawes1984]

Is there any possible way to locate an AC system leak **without** pressurizing the system? I have a leak obviously, so I began replacing various o-rings in an attempt to repair it. Pulled a quick "test" vac on the system, and it would not hold vacuum.

I really don't want to inject dye and charge it with expensive R134 just for it to all leak back out again trying to find the leak. I don't have nitrogen available, and shop air is full of moisture, so I really don't think that's a good idea.

Aside from shooting in the dark (vacuum, test, replace o-rings) is there any other methods I can use to identify exactly where my leak may be coming from? I've already replaced several o-rings in the system and still have a handful that I can replace but would prefer not to if I could keep from it.

 

[MrBubba]

Aside from visually looking for spots that indicate potential leaks nitrogen is the preferred method, some use shop air but isn't preferred although you still need to pull a vacuum to remove moisture anyway.

Why stop half way through on replacing o-rings? replace all that can be replaced to prevent future leaks.

 

[SC Maintenance]

I proposed pressurizing mine with air. Its 78% nitrogen. People here thought it was a very bad idea so I didn't.

 

[bdcardinal]

Could you maybe have lucked out and there was dye in there already?

 

[RooflessVW]

Fill it with shop air then change the dryer and pull a hard vacuum for 15-30 minutes. The moisture will boil off.

 

[zzyzzx]

I also recommend compressed air.