I'm a noob to fixing things but i want to fix my car's AC, it's not blowing cold air.

I already had it topped up at a shop and i could hear it hissing when i turned it on, it was empty again within 24 hours and when i went back for some reason they bullshitted me and didnt check with a UV light for the leak or anything.

I want to learn do it myself, i'll order one of those kits with gauges and a vacuum pump and cans with refrigerant. I already thought about trying to change the valves in case thats where it leaks from, but if its somewhere else, can i just load some dye into the system somehow and then check with a uv flashlight to see where its leaking? Or do i have to put 500gr of premixed refrigerant and let it leak again, cause that would be pricey.

Whats the best way to go about this? Thanks.

They must have left the service port open or broke it if it was hissing when you turned on the AC only for it to leak in 24 hrs. Sounds like your issue. Pun optionally intended.

>>28456373
It was hissing before i went there. They topped it off, said it holds pressure just fine and sent me on my way. Next day it was empty again and blew hot air. I went and got my money back but the issue isnt fixed and i have to do it myself.

Its illegal to put there any refrigant because it leaks

>>28456363 (OP)
First thing is a thorough underhood inspection looking for oily build-up on A/C components, particularly hose crimps and the most exposed areas of the condenser. There will be some fresh oil on the charging ports since somebody was just there but if there's black oily dirt surrounding that then that may indicate a leak there. Any parts with oily build up indicate a leak and need to be replaced.

If everything looks dry then it suggests an evaporator leak, or at least a leak inside the evaporator case so you would need to get the system charged with a dyed refrigerant if it wasn't already, and run it for a couple hours and then use one of those kits with a black light and yellow goggles to look for dye coming out of the A/C condensate drain from under the car. Also double check every hose and connection under the hood with this too. BTW there are halogen leak detectors but that could detect a leak in seconds but they're too expensive for a backyarder so the dye is pretty much your only choice.

Whatever the problem is, it's going to cost a thousand bucks to fix. Every A/C problem I ever had bar one cost a thousand bucks. If you believe that shop and it held pressure for them, but leaked after you used it? perhaps the shaft seal on the compressor is dead, new compressor, thousand bucks.

A/C is a luxury item, thousand buckos, bucko

Even used parts to assemble an AC is a fuckin lot.

>>28456363 (OP)
Replace schrader valves and drier
Check for any other leaks while you're at it
If your car is old and has never had an AC job, do the compressor shaft seal too, they get hard and leak eventually

>>28456363 (OP)
The filter.
Check the fucking filter.

>>28456434
That's only for R12 and real R134A. Most shit used in car AC systems is synthetic versions of that and are fine to release into the atmosphere.

>>28456526
>>28456553
What do you people drive? A full chinesium AC system for my GM's is like ~$300.

First thing would be to install a new ac o-ring kit and orifice tube (since it sounds like your ac compressor clutch is working and kicks on). Very easy and straight forward job, just disconnect the refrigerant lines and put new o-rings in wherever they come out. Orifice tube will be after the condenser (the 2nd radiator thats usually mounted in front of the radiator) and before the evaporator (tube leads from the condenser to an air plenum (black box on passenger side firewall) and the evaporator is in this box). After that is just vacuuming the system with a vacuum pump and seeing that it holds vacuum for ≈ 24h, then introducing the proper amount of refrigerant. The job is extremely cheap at less than $30 in parts and very few tools needed, which is wrenches only usually (buy fluid wrenches if youre the tool collector type, also napa sells 2 sets of crows feet that are like fluid wrenches but i think i remember having issues with them not fitting on flexible rubber ac lines on my 1983 gmc). Otherwise youll need to rent the vacuum pump and ac manifold gauge tools, at autozone it will be ≈ $400 for pump and gauge rental, but all that money is returned upon return of the rental tools. Then introduce the refrigerant into the low pressure side (see pic related) until youve got the right amount of it (buy a chilton or haynes by asking for one for your car at the autoparts store).

>>28456363 (OP)
>i could hear it hissing when i turned it on
Fuck. I am sorry anon, but I think you need to buy a new car. AC hissing means that it is releasing CO gas, it can kill you and there isn't a way to fix.

>>28458029
lol