How to fix leaking air conditioning schrader valve

Question

I have a 98 jeep cheerokee sport. The air conditioning coolant leaks. After doing some diagnostics, I detected audibly a hissing sound coming from the low input port, leading me to believe the schrader valve is leaking.

How do I determine which valve core remover tool fits my vehicle? I have found one from Mastercool and one from Interdynamics. I am pretty sure I bought one of these before and it didnt work, because it supposed that the car had a thread around the outside of the low input port for it to "connect to", whereas on the jeep, there is no thread on the outside of the port, its actually on the inside of the port, as pictured below.

Furthermore, I have read that instead of replacing the valve, you can simply use plumbers tape around the inside of the cap, and an "o-ring" (though where that goes I dont know). If I took this approach (instead of using the valve core tool) how would I get plumbers tape inside the port (or inside the cap) around the threads, since theres so little space?

Further, how do I find the correct "o-ring" and how would I install it? I've read people do this with metal caps but I only found plastic ones for my jeep online and at my auto store.

Edit 11/13: Upon further inspection, it appears that the O-Ring is on the inside of the schrader valve cap. Any tips on getting it out? I've read that the cap and this ring is what provides the definitive seal, so if I replace this, I'm guessing it can do as a work-around solution. Ideally though I'd like to do both (replace the o-ring and the valve).

Answer 1

I would go ahead and replace both the valve and the o-ring. Also, you most likely have the R134a, as this has become the standard for automobile Acs for the time being. As far as getting the right parts? Try calling Jeep, and getting some part numbers. When you get down to specific small items like these, I doubt aftermarket parts are available. Once replaced, ensure that the vacuum holds on the laking cap, before wasting money on the refrigerant.

Answer 2

The Shrader valve is the definitive seal. The cap is there to keep dirt & crud out of the Shrader valve. The plastic threads on those caps aren't enough to hold more than a few pounds of pressure, and there's no way to get Teflon plumber's tape on those threads.

So... you might replace the Shrader valve, or at least reseat it (that often does the job - just loosen & retighten several times). DO THIS with NO pressure on the AC system! Under pressure, a Shrader valve can go through your chest very much like a small bullet.

Answer 3

Doorman and others make a valve removal tool that comes with both high low PSI fittings.

It snaps on to the valve head then you connect then removal portion that has a ball-cock. Start by connecting to which ever valve and remove inner Schrader valve it will blow valve up into tube and then shut ball cock and unscrew top tube remove bad Schrader and insert new Schrader valve and reattach tube to the tool and open ball cock lever and use the top handle to screw in new Schrader valve. Then just lift the collar on the removal tube and your done.

Do a search on Google you'll find the tool at parts stores for about 39 dollars. Once you see the tool these instructions will make better since. You won't lose any gas this way.