Low Pressure Port A/C
 

The A/C Blows cold and works great. I checked the system for leaks and everything is AOK except for the low pressure port. A/C is starting to get warm.


I've read on the forum just wiggle the valve and it might reseat (haven't tried it yet though). And I'm missing my cap. So I read where just replacing the cap will stop it? I never knew the cap to hold pressure, but more of just a "cap".


Is there anyway to replace just the port? I didn't see it anywhere here.


I found = Supercool LOW SIDE FITTING FOR R134A | Product Details | Pep Boys So I can assume you can?

The cap doesn't hold pressure. Don't wiggle, do it properly - sounds worth taking to an a/c guy in this case. Expect a small price. Be aware the gas is a hazard to your health.

Reclaim refrigerant, remove the valve and take to auto parts store for match-up, reinstall valve, recharge system.

bob gauff

You mentioned the AC is already starting to get warm. That means the system will need to be recharged. Are you comfortable doing this yourself? Do you have the equipment?

If no to either question, you'll have to have it professionally done. The leak you've described is a very simple repair that will hardly add to the bill. Most shops would rather work the entire job instead of hoping your repair was done properly.

If you are prepared to do everything yourself, the repair is quite simple. Inside the port is a valve core, just like what's inside the valve stem on a tire. My first guess is it has unthreaded slightly. Use a valve core tool (available from any parts store) and see if you can tighten it. Wrap a rag around the tool and keep your face clear in case any refrigerant is accidentally released. Wear goggles, too.

If that doesn't stop the leak, there may be debris in the valve core. In that case, depressing the valve plunger for a brief blast may clear it. Once again, wrap a rag around the tool and keep your face well out of the way. Don't forget the eye protection.

If that fixes the leak, the system will still have to be recharged. The official party line is the system should be fully evacuated and refilled with a measured amount. In practice, though, if the system still has a partial charge (meaning moisture hasn't been able to get in the system), I've gotten away with SLOWLY adding refrigerant until the outlet temp returns to normal.

It is a Schrader valve and does have a core, but it's a larger diameter than a tire valve stem, there is a specific tool to remove / tighten them.

Sure you can add refrigerant to a "low" system and get it cold again, and there is a drier In the system to remove modest amounts of moisture. But if freon can get out, air (and resultant moisture can get in).

The bigger question in all this is, how does the OP know or believe that the leak is at the Low pressure fill port? 90% of the leaks I have seen on Jags are at the compressor itself. Look at the compressor and check for signs of a green stain of green slime. (The oil used to lubricate the compressor) only way to properly tell is to add uv dye to the system and get out the black light and goggles.

Take care.

George

Sorry just got back into town.


I had my bud that does AC look at it for me. He used dye and no leaks, but it was slowly coming from the low pressure port. The valve inside is faulty. If you just barely wiggle it, it stops. So we tried tightening it, but it's just bad. I have to replace it. So far, it's keeping cool after we recharged it...but it needs replacing. Now just to find out what part will work for it.

Doesn't the a/c guy have them? I'd expect him to!

A/C Schrader valves are standard. Just to to a parts store and ask for a low side pressure port valve.

They make a special tool to remove / replace them while losing just a bit of refrigerant.

http://www.tooltopia.com/mastercool-...aign=nextag_r1

Hope this helps.

Take care,

George

He does, going to send me one. He said he was going to send me down a couple not to buy any. He's a buddy from out of town so we got together for a few drinks. :) But while he was here, I put him to work ha!


Other than that, the AC works great!

I just can't seem to locate the low pressure port on my S-Type. I've looked everywhere, even behind the drivers side wheel well. Can anyone help?


Thanks

George that's a cool tool! Never seen it before.

I don't understand how it can take the old valve out and install the new one?

It does have a handle for controlling the pressure?
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Here you go, quality is not the best but you get the idea.

OK, this is an old thread, but I ran across it while searching for whether the Jag ac port takes a standard cap (found out the cap from a 2000 Toyota doesn't thread into the Jag port), and thought some other info I found may be of future use to someone.

According to an authoritative-sounding GM tech in this thread https://autoacforum.com/messageview....threadid=21914 a good port cap should indeed seal the system against leaks from a faulty schrader valve, so that might provide a quick and easy fix for some, maybe avoiding a complete evac and recharge. Also good to know in case you're tempted to just not bother replacing a lost or missing cap.

While doing some work on my granddaughter's 1996 XJ6, I noticed it was leaking slowly at the low pressure service port. There was a small amount of the green oil in the uncapped port, and tiny bubbles coming up through it. I flicked the valve a few times and it got better, but didn't completely stop. This may explain why her system has lost coolant over time, but showed no pressure loss overnight with a gauge attached to it...attached at that port, of course, so keeping it from leaking there.

Off to the parts store tomorrow to get a cap for it...hope the standard one fits the Jag.