A/c Valve Leak

the hammer · August 27, 2010

I have not checked the A/C pressure in the 4 years i have had my truck, and I thought since it seemed to be getting a little warmer I would put an A/C pressure gauge on it and top off the freon if needed. Well, needless to say the valve stuck and it is just leaking out vapor and freon now.

Can I change out the schrader valve or do I need to replace a heck of a lot of parts all because of this valve leaking? Any help appreciated.

Wires · August 27, 2010

I have not checked the A/C pressure in the 4 years i have had my truck, and I thought since it seemed to be getting a little warmer I would put an A/C pressure gauge on it and top off the freon if needed. Well, needless to say the valve stuck and it is just leaking out vapor and freon now.

Can I change out the schrader valve or do I need to replace a heck of a lot of parts all because of this valve leaking? Any help appreciated.

You should be able to just replace the valve, but you're going to want to put it under a vacuum afterwards to make sure no air/moisture is in the system before recharging. If you can swap it while it's leaking, then no worries, but you may have frosty fingers afterwards....

That definately sucks though.

the hammer · August 27, 2010

I figured I could use this and switch out the valve: Mastercool Valve Tool

Wires · August 27, 2010

I figured I could use this and switch out the valve: Mastercool Valve Tool

Looks like you could do that with the system pressurized, but I've never swapped the valve, so maybe someone that has can chime in.

dcockrum · September 6, 2010

me too. low side valve. It seemed like the dust cap made the leak stop. Maybe it didn't and it was just quieter. In any case, anybody have experience with this? Does the tool mentioned above allow replacement of the valve core without discharging the system? Is it possible the dust cap is actually containing the low side pressure?

ken1mod · September 6, 2010

The valve insert is the same as tires use and the tire tool works. Usually, these valve pins just get stuck and jiggering it lets it seat perfectly. Rarely do you need to replace the insert. The cap is the real seal. These also do not leak if the oring is ok.

Ken

jblakeney · September 6, 2010

The high side uses a ball seal. After the system has been ran for several months. Once you clip on be prepared for the horror.... The coupler usually wreck the ball and requires that you replace the fitting. Four Seasons 409-521 (I think, I remember that right, that should be the NAPA number)...

It requires you drain (recover........ vent) R134a. Then remove the fitting and also replace the low side if necessary...... While doing this you should know that you NEED TO VACUUM THE SYSTEM back down to remove moisture. 1 hour of vacuum, will do the trick nicely. Get new caps also, as ken said above that really seal it all off good....

If the system has not been preforming well, might not be a bad idea to change the orifice tube while your at it...

I have no less than 4 of these fittings in my tool box.... It is a frequent problem. And if you don't vacuum it down shame shame shame.... You just introduced moisture into your system. It has now began the death dance.

Jbo

GPSilverado · September 6, 2010

The high side uses a ball seal. After the system has been ran for several months. Once you clip on be prepared for the horror.... The coupler usually wreck the ball and requires that you replace the fitting. Four Seasons 409-521 (I think, I remember that right, that should be the NAPA number)...

It requires you drain (recover........ vent) R134a. Then remove the fitting and also replace the low side if necessary...... While doing this you should know that you NEED TO VACUUM THE SYSTEM back down to remove moisture. 1 hour of vacuum, will do the trick nicely. Get new caps also, as ken said above that really seal it all off good....

If the system has not been preforming well, might not be a bad idea to change the orifice tube while your at it...

I have no less than 4 of these fittings in my tool box.... It is a frequent problem. And if you don't vacuum it down shame shame shame.... You just introduced moisture into your system. It has now began the death dance.

Jbo

I agree 100%, except in the case where the system still has positive pressure in it, and the tool referenced above is used. That tool allows the valve to be replaced while the system is pressurized, and no moisture is introduced to the system. If however, all pressure has already escaped, then the system needs to have a vacuum pulled on it.

I can't believe I am up this early to go fishing... While playing golf on Sunday, one of the guys that joined our group said that anyone that went fishing must have absolutely nothing else to do. He's now going fishing with us today

jblakeney · September 7, 2010

The high side uses a ball seal. After the system has been ran for several months. Once you clip on be prepared for the horror.... The coupler usually wreck the ball and requires that you replace the fitting. Four Seasons 409-521 (I think, I remember that right, that should be the NAPA number)...

It requires you drain (recover........ vent) R134a. Then remove the fitting and also replace the low side if necessary...... While doing this you should know that you NEED TO VACUUM THE SYSTEM back down to remove moisture. 1 hour of vacuum, will do the trick nicely. Get new caps also, as ken said above that really seal it all off good....

If the system has not been preforming well, might not be a bad idea to change the orifice tube while your at it...

I have no less than 4 of these fittings in my tool box.... It is a frequent problem. And if you don't vacuum it down shame shame shame.... You just introduced moisture into your system. It has now began the death dance.

Jbo

I agree 100%, except in the case where the system still has positive pressure in it, and the tool referenced above is used. That tool allows the valve to be replaced while the system is pressurized, and no moisture is introduced to the system. If however, all pressure has already escaped, then the system needs to have a vacuum pulled on it.

I can't believe I am up this early to go fishing... While playing golf on Sunday, one of the guys that joined our group said that anyone that went fishing must have absolutely nothing else to do. He's now going fishing with us today

GM does not have a valve core on the high side. They use a ball seal.... It requires complete replacement..... TEM 409521 (GM High Side Most vehicles all GMT-800's) you can not leave the pressure in the system and change this. Low side is a valve stem. Most leaks on GM's is the high side.

JBo