Sure, it'll usually work - but for how long? When I do a conversion I only want to do it once, not to mention spending the money!Sounds like a nightmare, but it works. Old hoses, old o-rings, ester oil. I have heard of people not even evacuating, just adding the 134a on what little r12 was left. I would not recommend doing that, but apparently people have tried it and it works.
I have done several by installing conversion fittings, evacuating, checking for leaks, and then adding the r134a/ester oil combo cans and had them work well.
Also expensive, not to mention illegalAnd that leads to my next suggestion of finding the leak before doing anything. Because if the r12 is gone, it went somewhere, and gassing up a leaking system isn't right and is a recipe for a comeback IMO.
Sure, it'll usually work - but for how long? When I do a conversion I only want to do it once, not to mention spending the money!
I'd like to see where it's illegal at as well, because I can guarantee you that 90+% of the hand grenades sold at every walmart and auto parts store are being bought by the general public and going into leakers that won't be fixed. There's an entire industry based solely off of that(hello a/c pro, etc.)
Is it right? No. Should the leak be found? Sure. Will it be found? Not until they quit selling it to the general public.
Now if you're talking about 609 certs and techs that are, that's altogether different. But again, being certified isn't a requirement to purchase r134a in the cans at any quantity, and until that changes, there will be leaks that aren't fixed.
About that same time frame I would buy mine on clearance at our local farm and home store at the beginning of winter for $1.99 a can. I would buy 2 cases of 12 every year.Couple years back, at least under Trump, the small cans of R-134 were around $4
. Let's just say in my experience propane/butane works very well.