Ever changed a/c expansion valve? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

chevydog66 · 07-30-2013, 10:38 PM

I recently had my a/c vacced and charged in my 72 GMC truck with 6.0 ls running the new Sanden 508 compressor with R134. It is working but I have a very small leak between the top 2 jamb nuts on the expansion valve. I tried tightening them but no luck. I noticed that a sensor line runs into the evap core. Looks like its not easy to change. I totally rebuilt the heat/ac box last year while the truck was getting painted. Any ideas?

88fordf150 · 07-31-2013, 09:06 AM

Take it back to whoever charged the system. If it won't seal by tightening it the charge will have to come out to be repaired. They should charge the system with nitrogen to check the repair before re-charging again.

mrein3 · 07-31-2013, 11:28 AM

There is an o-ring there. It probably needs to be replaced.
Posted via Mobile Device

chevydog66 · 07-31-2013, 02:34 PM

A friend charged it for me. I installed all new o rings lubed with pag oil. LMC catalog or factory assembly manual doesn't show a o ring in there. But I'll check.
Posted via Mobile Device

07-30-2013, 10:38 PM	#1
chevydog66 GM ONLY BABY!!! Join Date: Oct 2003 Location: Fort Wayne, IN. Posts: 1,998	Ever changed a/c expansion valve? I recently had my a/c vacced and charged in my 72 GMC truck with 6.0 ls running the new Sanden 508 compressor with R134. It is working but I have a very small leak between the top 2 jamb nuts on the expansion valve. I tried tightening them but no luck. I noticed that a sensor line runs into the evap core. Looks like its not easy to change. I totally rebuilt the heat/ac box last year while the truck was getting painted. Any ideas? __________________ 2 wrongs don't make a right, but 3 lefts do. 66 Chevelle Malibu 406ci, 573hp, 10.99@121mph 96 Chevy Silverado Z71 72 GMC 1500 Super Custom LS 6.0/4L65 on airride http://www.cardomain.com/ride/707879...mc-c-k-pick-up

07-31-2013, 09:06 AM	#2
88fordf150 Registered User Join Date: Nov 2009 Location: Michigan Posts: 474	Re: Ever changed a/c expansion valve? Take it back to whoever charged the system. If it won't seal by tightening it the charge will have to come out to be repaired. They should charge the system with nitrogen to check the repair before re-charging again. __________________ Brad handshoe

07-31-2013, 11:28 AM	#3
mrein3 Registered User Join Date: Feb 2000 Location: Center City, MN, USA Posts: 3,254	Re: Ever changed a/c expansion valve? There is an o-ring there. It probably needs to be replaced. Posted via Mobile Device __________________ '70 cab, '71 chassis, 383, TH350, NP205. '71 Malibu convertible '72 Malibu hard top Center City, MN

07-31-2013, 02:34 PM	#4
chevydog66 GM ONLY BABY!!! Join Date: Oct 2003 Location: Fort Wayne, IN. Posts: 1,998	Re: Ever changed a/c expansion valve? A friend charged it for me. I installed all new o rings lubed with pag oil. LMC catalog or factory assembly manual doesn't show a o ring in there. But I'll check. Posted via Mobile Device __________________ 2 wrongs don't make a right, but 3 lefts do. 66 Chevelle Malibu 406ci, 573hp, 10.99@121mph 96 Chevy Silverado Z71 72 GMC 1500 Super Custom LS 6.0/4L65 on airride http://www.cardomain.com/ride/707879...mc-c-k-pick-up

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