A friend told me to seal off at the 90 degree rubber elbow, that connects to the compressor outlet to the ic piping, with pvc cap and use a worm gear to tighten it down. Then I would drill a small hole at the center of the cap insert some type of valved fitting like the ones on a tire, then spray a mixture of dishsoap and water on all the silicone couplings and welded connections on the piping, then pressurize it with a bicycle pump or lightly with an air compressor. You would then look for bubbles that would indicate an air leak. Can I use anything else like some type of gas that would physically show a leak?

 

This is something alone the lines that you're talking about:
https://honda-tech.com/zerothread?id=691168

 

Yeah that's pretty much the same but as far as some type of gas how about using co2? Any ideas on type of fitting for c02 cartridge?