leaking AC HP/LP ports (no valve .. sealed?) - Truck Forums

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Old 05-06-2010, 07:43 PM
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Join Date: May 2010
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Default leaking AC HP/LP ports (no valve .. sealed?)

Im hoping someone here might be able to point me in the right direction.
Last year i was working cleaning up the engine bay on a 2002 silverado 5.3L.
I uncapped both the HP anbd low pressure ports (just the plastic caps) to clean them ... and noticed 2 things .. one leading the the next.

1st it sounded like a very small leak when i removed the cap (small pop on removal) on the forward unit (high pressure i think) and unlike any other AC i remember instead of a valve within .. it looked like small sealed hole.

After toying with the cap .. the only time it leaked was with the plastic cap off .. little soap and water to be sure on how small the leak was .. and if it was leaking with the cap on.

Now a year later while the wife was driving it looks like it blew the cap off and and seems to have dropped most of the oil and refrigirant (guessing).
It still has some pressure on the line .. small hiss .. but it definately blew the cap completely off and vented a LOT.

Whats the recommended way to check .. and replace it. (or even just the AC level). Manifold gauges wont attach to it that way

If it doesnt have a schrader valve to seal that port... why have it there at all? unless there something special im missing .. and if it did leak and blow out the seal that was there .. guessing the entire line needs replaced

Well i stand corrected.. i appears to actually be a valve but not a replaceable schrader type .. so if that seal if kaput ... then entire unit line had to be replaced... or so it appears at this point

Last edited by Seering; 05-06-2010 at 08:15 PM.
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Old 05-06-2010, 09:45 PM
Mr_Shamrock's Avatar
Chevrolet/GMC, Racing, Recreational Forum Moderator
Join Date: Apr 2009
Posts: 2,267

Actually it will unscrew and is replaceable. It is the high side and I just had one leaking on my Suburban. It does not look like it unscrews, but it does and they are famous for leaking. I picked mine up at O'reilly's for like $10.00. Good luck!
2003 Chevrolet Tahoe 4X4 5.3
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Old 05-22-2010, 05:23 AM
Join Date: Mar 2010
Posts: 33

I know this is an old thread but for future reference here is what I did when facing the same problem on another truck. I was have the same issue, the AC worked fine but it leaked around the high pressure AND low pressure ports. I went to John Deere and bought ports for a 4960 tractor! It is heavy duty and made of solid brass. I paid 40 bucks for both the high and low side. I never had another problem..
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Old 07-02-2010, 03:04 PM
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Join Date: Jun 2010
Posts: 2

I'm having the same problem with my 99 Suburban TD. The dealer replaced the entire assembly because it was leaking and now this one is leaking. Do you know if the ports for the 4960 tractor will fit my 99 GMC Suburban? If not, how do I size it to do what you did? How did you figure out that the 4960 was an exact fit? Thank you in advance for your assistance.
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Old 07-04-2010, 07:42 PM
Join Date: Mar 2010
Posts: 33

It should be the same on ALL 134 AC systems. At least all the ones Ive seen are.
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