Leak AC location found.. now what?

Help me.. I'm newbie here and not much of a mechanic.
I have 1996 Taco extra cab. It ran out of AC over a year now and want to fix it myself.
I found the leak area, right @ the neck of that nut - see photo.
I know how to take off the grill but don't know what to do next. Should I go ahead and tight up that nut and fill it with coolant?
Your help would be much appreciated. Thanks.

 

How do you know it’s leaking there?
If you know for sure, that should be sealed by an O-ring and as long as the system is fully discharged you can simply unscrew that nut and replace the O-ring.
the key is FULLY DISCHARGED, if its not take it somewhere and at least have the system pulled down so you can replace the seal. If it’s empty and you’re gonna do this yourself be sure to put 2 wrenches on it, one holding the nut on the line and another turning the big nut, they’re usually not real tight but you don’t want to twist the aluminum tube. Good luck..

 

Pretty sure about that spot. I tried to pump in new coolant and that's where it shot out. Like a geyser. About this O-ring, is it a special kind? Any O-ring would do? It looks like a 3/8". Ok, now I know what to do next. Thanks.

 

https://www.rockauto.com/en/catalog.../c+system+o-rings,+seals,+&+gasket+kits,13290

 

Before all the trouble I would double check for more leaks it sucks to fix one and find two more.

 

If I had a 1996 truck (mileage unknown - not stated) and limited mechanical abilities, I would take it to an AC specialist and have the whole thing checked out. Who knows what other seals are shot. I wouldn't futz around with adding "coolant". Let a specialist pull a vacuum, check the seals and schraeder valves, fill the system with something that contains dye, and then run the AC for 15 or so minutes to locate leaks. Then he can tell what it will cost to fix it. If you don't his estimate, take it to another AC specialist and see what he says.

After the leaks have been fixed, the mechanic will recharge the system with refrigerant (R-135A I assume), take your $$ and you can be on your way. I would guess, from my experience, that a complete system check, a minor fix, and system recharge will be around $150. That's what I paid last year to find and replace a leaky schraeder valve. Refrigerant ain't cheap, neither is the equipment to replace it.

And I would ask around to find a decent AC mechanic. Maybe your friends or your family know of somebody that they trust and that isn't going to rob you. 'Specially this time of year.

 

Great video, I recommend. If I remember correctly he has another great a/c video on his channel with an Accord or Camry where he has some great visuals

https://www.youtube.com/watch?v=BXTZURC5iQ0

 

Fix the leak and fill with refrigeration. It is $20 experiment.