can not locate ac freon leak.

[chris989]

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]

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

[jerry moss]

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]

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]

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.

[chris989]

Made it to the shop today,,, AC off,, temperature is 85 inside the garage,, The AC system has 106 psi,, It gained ~6psi due to ambient temp....

I will cool the garage back to 74 and see if it equalized back to 100psi,,, If it does,, I guess i will charge the system again and cross my fingers?

[hatzie]

I always change the service valves when I work on AC.

Giving the condensate puddle on the driveway a once over with the blacklight might reveal an evaporator leak.

[v30crewcab]

I had one slowly leaking down. pulled the valve core out of one inlet and it was missing the little sealing gasket on it. put a new one in and good to go.

[chris989]

Update,

Charged the system and sure enough it leaked even after holding 100 psi for over 30 hours.

Today i started pulling it apart.. I removed the shroud and leaned the radiator back and sure enough there is dye on the radiator.. Using the blacklight and glasses i can see a stain on the condenser although not green. A few green drops appear on the engine radiator..

My guess is when it gets hot and builds over 200 psi a tiny pinhole leaks and the fan/wind pulls it into the radiator..

Anyway,,, pumping it back down again with a new condenser. I took a few pictures but it doesn't show anything


Chris

[jjzepplin]

In For results.

[chris989]

Originally Posted by jjzepplin

In For results.

the new condenser is smaller and thinner than the OEM. When i started the truck i noticed the high pressure nearing 375 and that is not average for this build.

THe fans shrouds were off and I hope that is the factor.. I will run the truck toady and check vent temps..

[hatzie]

Originally Posted by chris989

the new condenser is smaller and thinner than the OEM. When i started the truck i noticed the high pressure nearing 375 and that is not average for this build.

THe fans shrouds were off and I hope that is the factor.. I will run the truck toady and check vent temps..

Is the filter in the orifice valve full of crud?

What's your low side pressure running?