GM High Pressure AC Line Valve

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4,479
Location
Kuwait
Roughly 3 weeks ago, I took the Envoy in for an AC service at the GMC dealer, something I do annually given local weather conditions. The system was slightly low (0.3 lb - total capacity 1.9 lb), but there were no leaks or other issues. The tech performing the service this time explicitly said he does not use the high pressure line, because of the valve's tendency to fail and only hooked up the machine to the low pressure line on the receiver drier. Strange, but okay...whatever.

Yesterday, I noticed PAG oil around the valve on the high pressure line/evaporator tube leading to the condenser. Since the valve has never been replaced, and is 15 years old, I guess it's time to replace it. Only problem is, it appears GM does not sell the valve separately and wants you to buy the entire tube assembly - Reference 8 in the diagram (P/N: 15923988):



My guess is the valve was so problematic, GM decided to do away with it altogether and save money by not integrating one into replacements. The valve looks like a metric 16, which can easily be removed.

This is what the GM Original Equipment replacement looks like:



This is what an aftermarket line from UAC looks like with the valve:



Not sure where to go from here; replace the tube with the valve delete that superseded the factory line, or just buy a valve, replace it and call it a day. Would love to hear from any HVAC professionals onboard. :)

Should I end up replacing the valve, does anyone have the GM part number or know of a decent aftermarket replacement with a better seal? Thanks!
 
Messages
21,869
Location
Apple Valley, California
I am shocked that the dealer does not replace valves and ports with every recharge. I keep all kinds in stock and replace them on every car I work on.

If I don't replace them they are guaranteed to leak when I take the hoses off.

Also ac machines will not inject oil through the low side. The op lost some oil with the evac and charge and it must he replaced!

The ports I mentioned in the above thread are available from any auto parts store. I buy them in packs of 5 from Autozone as they have the best pricing.

You can also buy the pack of caps and valves for any car and it has shraders ,caps and ports for about $10.
 

Falcon_LS

Thread starter
Messages
4,479
Location
Kuwait
Thank you very much for everyone's input; definitely learned a lot more than I ever expected! Never realized the valves were to be replaced at every service, and the fact that the AC machine does not inject oil through the low side!

I ended up ordering both valves with new caps, and will take it from there. (y)
 
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