I'm doing the AC dance on my '82 300SD - new compressor, parallel flow condenser, replace some leaking hoses, etc..

What I'm wondering is, can CO2/Argon mix be used to check for leaks? I know nitrogen/dry air is better, but you see, I've got this cylinder of welding gas already.. would be nice if I could use that..

I want to pressurize with 50 psi of CO2/Argon, and see if it holds pressure. Good idea/Bad idea?

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'82 300SD 351k