Find Hole in AC Line?
 

very basic question but how do I locate a hole in my AC line?

The previous owner had some paperwork from their mechanic mentioning a hole in the AC line which leaked out all the gas. They quoted $600 to repair and refill. Unfortunately the paperwork doesn’t indicate where the hole was located and the shop has since closed.

How can I best locate a hole in the system? I can’t find any info on AC lines or repairing them

2004 X5 4.4i

Here is one suggestion from Rob Siegel aka BMW CCA Roundel Magazine Hack Mechanic.
https://www.hagerty.com/media/opinio...ssure-testing/

He uses nitrogen to fill the system and then uses a soapy solution to find bubbles.
You could also use compressed air, but compressed air has moisture in it, which is not good for AC systems - although you will likely want to replace your receiver drier anyway..

Before you do this, you might get a UV flashlight and glasses and see if you can find traces of UV dye anywhere along the AC system. My guess is a previous mechanic added UV dye to the oil or refrigerant and used it to find the leak...there still may be traced of it on your lines.

The UV dye, glasses and flashlight come in handy tracing hard-to-find coolant leaks as well.

If there is a major leak such as a hole that has been open for a while you might be better off taking it to an A/C shop. Nitrogen would probably be the best way to find the leak/hole but after that there will be likely more to do.

Haha I'm a slow typer! ;)

If a line has a hole in it, check for rubbing marks. Especially around bends and brackets. Or replace the hoses, dryer, and stuff and charge it up.

Also, don't assume that there's actually a hole. These cars are known for defective schrader valves. The diagnostic may have simply been "it comes out real fast."

Net-net, though, you want to pressurize the system and look for leaks. A hydrocarbon detector is really useful for this sort of thing too.

A vacuum pull will indicate how big of a leak. If there is no leak and it holds vacuum, the valve cores are bad.