can not locate ac freon leak. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

chris989 · Yesterday, 06:06 PM

Hello all,

1989 v2500,,,5.7

This is my 3rd time trying to find this leak,,, after converting to sanden, the system will pull a vac and hold over night. But when charged it will lose the freon after a week or two.

I then charged the system to 100 psi and it will hold forever. I replaced a suspect oring and charged.. 2 weeks,, low on gas.

It is not charged to 100 psi again,, and it will hold,, but i know it will lose gas afterwards,

Is it possible a leak presents itself when the metal expands or contracts in the evap or condensor due to temperatures??? Any guesses

72c20customcamper · Yesterday, 08:01 PM

Have you added dye to it . I had a similar issue with my 85 it ended up being the compressor seal

**jerry moss** · Yesterday, 09:25 PM

at work we always add dye to the system and go over everything we can see with a black light before we release the vehicle back to the customer then we have them come back in a few days and check it again.

chris989 · Yesterday, 09:33 PM

It has dye and i can not see any traces, The compressor is a new real sanden 4711 sd7

my gauges are Yellow jacket analog,

I have had a charge of 100 psi for 4 hours now and still dead on 100,

shop has AC and temperature is a steady 72. I ordered a new condenser and evap core but hate to go through the work to not have it solve the problem..

it has all new Galaxy hose (usa) and fittings,

My gauge is hooked to the filter.dryer,,, I can only think that when i remove it the schrader valve is leaking and with the gauge it is captured,,, I have soaped it with no bubbles.. I might hook a hose to the shrader and put the other end in a cup of soapy water??

Dead Parrot · Today, 09:41 AM

I have had good luck with the R12 version of this: https://www.autozone.com/a-c-chargin...2oz/370967_0_0

Replaced a compressor in the mid 90s and used one of those cans with oil, leak finder, leak sealer and freon. Only needed a couple of cans since until something failed in the back of the compressor a couple of years ago. A large oil stain implies something that exceeded the capacity of the leak stop to fix. Planning on doing a Sanden conversion at some point.

Might be worth a try of the R134 version.

Yesterday, 06:06 PM	#1
chris989 Registered User Join Date: Dec 2011 Location: Boise, Idaho Posts: 565	can not locate ac freon leak. Hello all, 1989 v2500,,,5.7 This is my 3rd time trying to find this leak,,, after converting to sanden, the system will pull a vac and hold over night. But when charged it will lose the freon after a week or two. I then charged the system to 100 psi and it will hold forever. I replaced a suspect oring and charged.. 2 weeks,, low on gas. It is not charged to 100 psi again,, and it will hold,, but i know it will lose gas afterwards, Is it possible a leak presents itself when the metal expands or contracts in the evap or condensor due to temperatures??? Any guesses

Yesterday, 08:01 PM	#2
72c20customcamper Registered User Join Date: Jul 2018 Location: Catskill Mountains,NY Posts: 8,413	Re: can not locate ac freon leak. Have you added dye to it . I had a similar issue with my 85 it ended up being the compressor seal __________________ Mark 72 c20 custom camper Husky edition, 66 SS396 Chevelle 1964 Hawk, 63 Avanti,62 lark 1969 AMX , 1968 c20 stepside ,85 K20 1977 Suburban sold 68 anniversary.

Yesterday, 09:25 PM	#3
jerry moss Born Psycho Join Date: Feb 2001 Location: brentwood,cal,usa Posts: 4,858	Re: can not locate ac freon leak. at work we always add dye to the system and go over everything we can see with a black light before we release the vehicle back to the customer then we have them come back in a few days and check it again. __________________ jerry moss 72 cheyenne super K20- tilt,tach,vacuum,speedwarning,buckets,shoulder belts,am/fm,tow hooks,bumper guards,toolbox,aux. fuel tank,posi front and rear,plus other goodies!!! SOLD 69 suburban K20-tilt,tach,vacuum,speedwarning,buckets,shoulder belts,am/fm,4 inch all spring lift,4 speed, 14 bolt full floater, dana 44 HD,warn winch,posi front and rear,tow hooks,plus other goodies. 73/80 chevy/gmc K20 SB400,turbo 400,205,tilt,a-c,gas hog. 77 K/5 cheyenne blazer-daily driver/beater. SON HAS IT NOW BRENTWOOD,CALIFORNIA

Yesterday, 09:33 PM	#4
chris989 Registered User Join Date: Dec 2011 Location: Boise, Idaho Posts: 565	Re: can not locate ac freon leak. It has dye and i can not see any traces, The compressor is a new real sanden 4711 sd7 my gauges are Yellow jacket analog, I have had a charge of 100 psi for 4 hours now and still dead on 100, shop has AC and temperature is a steady 72. I ordered a new condenser and evap core but hate to go through the work to not have it solve the problem.. it has all new Galaxy hose (usa) and fittings, My gauge is hooked to the filter.dryer,,, I can only think that when i remove it the schrader valve is leaking and with the gauge it is captured,,, I have soaped it with no bubbles.. I might hook a hose to the shrader and put the other end in a cup of soapy water??

Today, 09:41 AM	#5
Dead Parrot Registered User Join Date: Aug 2012 Location: Oklahoma City, OK Posts: 2,523	Re: can not locate ac freon leak. I have had good luck with the R12 version of this: https://www.autozone.com/a-c-chargin...2oz/370967_0_0 Replaced a compressor in the mid 90s and used one of those cans with oil, leak finder, leak sealer and freon. Only needed a couple of cans since until something failed in the back of the compressor a couple of years ago. A large oil stain implies something that exceeded the capacity of the leak stop to fix. Planning on doing a Sanden conversion at some point. Might be worth a try of the R134 version.



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