'97 Taurus GL 3.0L 194.6k: A/C High Press Test Port Leaking Constantly

[Colt Hero]

'97 Taurus GL 3.0L 194.6k: A/C High Press Test Port Leaking Constantly

I had the gauge set connected to both ports and was checking the static pressure, then the running pressure. With ambient around 89 F and humidity at 48 %, static was at 102-104-ish on both high and low. Then I pulled the gauge set off to check my '02 Impala and the Taurus' high pressure port starting spewing out what looked like mostly air (not a white cloud at all) out the high pressure test port. This happened to me last year but it stopped after putting the gauge set back on, then taking it off. This time, it wouldn't stop.

So I bought the tool/needle-core replacement kit ($3.49 at O'Reilly's). Problem is, if I take the gauge set off, it'll start leaking again and I doubt I'll be able to get the tool on it to try to tighten the core.

So do I just let it all blow out and THEN proceed, or do I try to capture the leaking refrigerant (R-134a) somehow?

And does anybody know of a pressurized fitting I can snap on to temporarily stop the leak? I'm thinking it would just be the fitting on the end of the gauge set, minus the hose. Is such a thing available anywhere (or could I make it)?

[shorod]

If it's not spewing with a lot of force, the factory fitting cap may contain the refrigerant.

-Rod

[danielsatur]

1) Recover 134a, put new schrader valves. vacuum, recharge with 134a.
I like the blue(low), and red (high) caps for a colored coded low/high pressure sides.

Big Lots has 134a for $8.00 a can.

[Colt Hero]

shorod:

The factory fitting cap is just a plastic "dust cover". It's not a pressurized cap (unless there's something on the inside that touches the core somehow which may help to seal it ... didn't check that).

You'd think with all the concern over refrigerant emmissions that they would require double valves on these test port stems. How hard would it be to put a ball valve below these pathetic Schrader valves???

danielsatur:

Recover how? ... at a professional's garage? I can't do that myself, can I?

These caps you're talking about are plastic, right? Do you know of any pressurized caps that can be snapped on? I was thinking that if I could find a hose from a gauge set that has the valves on the ends - that would work for me. At least then I could drive it somewhere to get it fixed. Right now I have the gauge set connected and sitting inside the engine cavity on top of the exhaust manifold (with the hoses tucked neatly away from the serp. belt/pulleys). Even though it APPEARS I could drive it this way, I really don't want to because the hoses could shift and if they touch the exhaust manifold they will burn or melt.

I stopped by Big Lots for the $8 cans and guess what ... "we just ran out of those". Yeah right! I used to work in retail as a kid. I know how that works...

[brcidd]

Originally Posted by Colt Hero

shorod:

The factory fitting cap is just a plastic "dust cover". It's not a pressurized cap (unless there's something on the inside that touches the core somehow which may help to seal it ... didn't check that).

..

This is absolutely wrong-- it is a pressure holding cap-- by design it is the primary seal- even though it is plastic it does have the rubber elemnet in there that seal off the system... I used to test them by pressurizing with no valve cores-- they hold to over 600 psi. seems hard to believe, but this is what it has come to -- the old steel caps are now plastic and are not dust covers....

I worked with the lines and hoses people in the assembly of GM units- and the caps are considered the primary seal... believe it or not- just put that cap on there and use your sniffer to tell if it is leaking....That's how I test them.

All valve cores leak-- heck that is how I test my sniffer is at the valve core fitting...

[Colt Hero]

Well, I believe what you're saying about your experience with the plastic caps, but THESE caps are REALLY flimsy. I'll check my Taurus shop manual to see if it mentions anything about these caps being anything more than "dust covers" - which, by the way, is the exact terminology used by the maker of the Schrader tool/core kit I purchased at O'Reilly's. The kit comes with replacement caps, but it calls them "dust covers". Now the kit might be wrong - I don't know. But like I said - I'll check the Taurus shop manual and see what it says.

But if it turns out they DO hold pressure, it might be dicey trying to get even THESE things back on the Schrader valve. What if I wait until the ambient temperature comes down - say at night? Do you think with the low temp (and pressure) that I'd have an easier time using the tool or getting the cap on? I think I'd like to try tightening the valve core since it MAY only be loose. I think it's worth a try - as long as I'm not gonna have to risk my hands and face to do it!

[brcidd]

I've had several caps in my 30 years pop up into my hand as I unscrew them- doesn't happen very often, because the biggest percentage of vehicles I see are low on refrigerant or even dead flat.....I did not believe it either, until I worked with the designers of lines and fittings group....no one wants to believe it-- But I have many times put caps on a spitting valve and the car never comes back.

I was told several times that the schrader valve is there to merely hold the refrigerant in long enough to get the cap on. So go ahead, buy new valves- suit yourself-- but if it were me, I'd by a box of new caps, so I have a good supply to replace those dicey caps.....I keep them right on my recovery machine..

[shorod]

I agree with brcidd. You might want to purchase OEM caps for your car. The Ford caps I've purchased have rubber seals in them and function just like brcidd mentioned. I have tested them with my leak detector, when the caps are a bit more than halfway loose the detector will start to alert. If I completely remove the cap and check the detector will go crazy. Put the caps on tightly and there is absolutely no indication once the immediate vicinity clears of refrigerant.

-Rod

[Colt Hero]

I was able to remove the gauge set this morning without anything leaking out of the test port. It was only 72 degrees ambient (instead of nearly 90 on Monday), so the lower system pressure must've been the difference.

As for the caps - sorry, but I'm still skeptical. A valve is supposed to close and not leak! The caps may have rubber seals on them to stop minor (early-stage) leaking, but I can't believe that the intent of the caps is to hold back 200+ psi of refrigerant on a hot day. If that were true, then the test gauges would also be sold with plastic caps and valves - and they're not ... they're all metal. The caps are there to keep dirt and debris from falling into the valve, and to also provide a minimal level of protection against a Schrader valve that (on a hot day) suddenly decides to fully open (and potentially spew refrigerant directly into someone's face).

I'm gonna check my original Ford caps to see if they have any seals inside. And I'll check the new ones in the kit, too. Maybe the kit ones are better than the originals because the seals were added later on when someone realized the Schraders would always be susceptible to parasitic leakage.

[brcidd]

Every schrader leaks-- just lay your sniffer on it for 24 hours, it will not stop whistling--case closed the caps are the seal.....

[Colt Hero]

brcidd:

I'm not arguing that Schraders don't leak. I'm arguing that the caps are NOT the seals. And it turns out this is exactly what the Ford Shop Manual says:

================================================== ================
SERVICE GAUGE PORT VALVES

The high side fitting is the largest. Special couplings are required to connect service equipment to both the high-side and low-side service ports. Refer to Special Service Equipment as described.

* Quick disconnects must be used to connect a manifold gauge set to the system

* Always install the A/C charging valve cap (19D702) on the service access gauge port valves after servicing the refrigerant system.

The service gauge port valves are either a one-piece or two-piece design:

* In the two-piece design, the aluminum top portion of the valve is threaded to the bottom port and sealed with an O-ring seal. The valve seal is an integral part of the aluminum fitting piece which must be replaced if the seal leaks.

* In the one-piece design, the valve is an integral part of the refrigeration line or component. The Schrader-type valve core can be replaced if the seal leaks
================================================== ================

Now, if the CAP was the seal, the manual wouldn't bother describing the valve designs and how they seal. It would just say, "... if the port leaks, replace the cap". And YES - the caps have gaskets. But these gaskets are only depicted in the drawing and not mentioned in the text as any kind of sealing agent ... which means they are either secondary sealants (for very minor leaks), or they are just there to prevent overtightening and cracking the caps.

Maybe on other cars the cap is the seal. I dunno. Or maybe you're thinking of the days before the plastic caps where metal caps were used. Maybe they were the seals? All I know is on the '97 Taurus, the plastic caps are little more than dust covers.

The Haynes manual, by the way, also calls the plastic caps "dust covers":

================================================== ===============
Adding Refrigerant (Step 11, page 3-12):

"... remove the dust cap from the low-side charging port and attach the quick-connect fitting on the kit hose..."
================================================== ===============

Enough on the caps ...