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A/C question

1985.5 NA

AC question. I have never attempted this but enjoying learning. I have replaced the compressor, condenser, dryer, o-rings and converted to R-134a. Holds vacuum. It calls for around 24 oz of refrigerant but after 12oz the high pressure is maxed out (with my ambient outside temp, manual recommends 258psi, if I add more refrigerant it goes much higher- like 350psi).

I have tried running water over the condenser to drop the pressure and am able to get the recommended amount in, however, when the condenser dries the pressure jumps back up.

coldest i could get with a wet condenser is 72 degrees F.

I will double check everything again. If i installed the dryer backwards would that effect the pressure...pretty sure I did it correctly....


What do you guys think is going on?

Old 06-23-2025, 02:59 PM
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Original amount is for R12. Do a conversion for R134a. But that still doesn't sound like that's your issue.
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Last edited by kdjones2000; 06-23-2025 at 08:05 PM..
Old 06-23-2025, 07:33 PM
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Seems like you have a blockage somewhere that's driving up the high side pressure.

Did you replace the Thermal Expansion Valve?
Old 06-24-2025, 03:22 AM
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It actually sounds like the fans are not turning on when the system is running and at pressure.

The circuit usually burns out in the fuse box so i just run a fan in front of the condenser that's triggered by the compressor clutch circuit.
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Old 06-24-2025, 11:23 AM
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Thanks for the reply. I’m kinda stuck right now, I don’t know much and was thinking the expansion valve might be the issue? Can you walk me through testing the fans?
Old 06-25-2025, 05:08 AM
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With the A/C turned on, both cooling fans should run constantly. Also when charging or testing, the inside blower fan should be running on high. So recheck your pressures and temps with all of the fans operating properly.

If you still have the problem try this guide: https://www.clarks-garage.com/shop-manual/hvac-02.htm

Old 06-25-2025, 02:36 PM
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