Here is what the designer of the charge ports says " Disagree all you want- but I worked with the designers of the lines and sealing folks at GM-- the caps are designed as the primary seal. I did not believe it at first either- but soon was made a believer when I ran numerous cap sealing test- with shrader valves removed-Obviously I charged the system from a different port--- anyway the caps are completely mandatory to maintain system sealing integrity"
Need AC support on 2000 accord
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Originally Posted By: Fleetmon
The caps are only to keep dirt out they are not meant to seal.....if you hear a hiss when you remove the cap, your schrader valve is bad.
The hiss is for a split second when unscrewing the cap - once the cap is off, no hiss, so the valves are working.
If the caps were just to keep dirt out, I think the manufacturers would prefer save the cost of an o-ring and molding a more complex cap. They would just make a plain "bottle cap" like you find on tire valve stems. These have threads that go down inside the valve, and the threads are sealed off by the o-ring.
The caps are only to keep dirt out they are not meant to seal.....if you hear a hiss when you remove the cap, your schrader valve is bad.
The hiss is for a split second when unscrewing the cap - once the cap is off, no hiss, so the valves are working.
If the caps were just to keep dirt out, I think the manufacturers would prefer save the cost of an o-ring and molding a more complex cap. They would just make a plain "bottle cap" like you find on tire valve stems. These have threads that go down inside the valve, and the threads are sealed off by the o-ring.
Turned out to be a bad accumulator ,
moisture in system , and slight overcharge.
Had my old mechanic whose a BIG crook vacuum , change the accumulator that i brought to him and charge to correct pressure.
Its not amazing , but its pretty good now.
moisture in system , and slight overcharge.
Had my old mechanic whose a BIG crook vacuum , change the accumulator that i brought to him and charge to correct pressure.
Its not amazing , but its pretty good now.
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Some of the caps actually do depress the schrader when installing/removing just a bit and just for a split second in order to (are you ready for this?) expel any dirt/contamination. If you pay real close attention to the cap on some designs, you'll note the cap thread "groove" elevates the cap just a bit when "tight".
Glad you got it fixed Voltmaster.
Glad you got it fixed Voltmaster.
Originally Posted By: Chris142
Here is what the designer of the charge ports says " Disagree all you want- but I worked with the designers of the lines and sealing folks at GM-- the caps are designed as the primary seal. I did not believe it at first either- but soon was made a believer when I ran numerous cap sealing test- with shrader valves removed-Obviously I charged the system from a different port--- anyway the caps are completely mandatory to maintain system sealing integrity"
Remember when I said originally that I was no kind of A/C expert?
Well, I just pulled the caps from the Tercel's A/C system to have a better look inside. These caps are plastic, but they do indeed have rubber gaskets in them. While I had the high side cap off, I peered very closely at the valve inside with a magnifying glass. And what do I see? A few teeny tiny bubbles around the edges of the valve. These were active bubbles, indicating that something was escaping from around the edges of the valve. The bubbles are not present on the low side, only the high.
So it looks like I was in fact wrong in that the cap does indeed perform a sealing function. Sorry, guys.
Here is what the designer of the charge ports says " Disagree all you want- but I worked with the designers of the lines and sealing folks at GM-- the caps are designed as the primary seal. I did not believe it at first either- but soon was made a believer when I ran numerous cap sealing test- with shrader valves removed-Obviously I charged the system from a different port--- anyway the caps are completely mandatory to maintain system sealing integrity"
Remember when I said originally that I was no kind of A/C expert?
Well, I just pulled the caps from the Tercel's A/C system to have a better look inside. These caps are plastic, but they do indeed have rubber gaskets in them. While I had the high side cap off, I peered very closely at the valve inside with a magnifying glass. And what do I see? A few teeny tiny bubbles around the edges of the valve. These were active bubbles, indicating that something was escaping from around the edges of the valve. The bubbles are not present on the low side, only the high.
So it looks like I was in fact wrong in that the cap does indeed perform a sealing function. Sorry, guys.
But can you do this experiment on a new vehicle? Is it possible that after the system ages, that valve starts slowly leaking and the cap is necessary to prevent that from happening? I too have hard time believing that the cap is supposed to hold that kind of pressure as its primary responsibility. That would be bad engineering.
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