AC Pressure Relief Valve woes

[heuster]

This is a LONG story that I'm going to try and cut short.
Last week I blew out all lines with air and solvent(front and rear evap, all lines to/from rear)
Put in a new fan clutch (aftermarket brand)
Followed that up with vacuum test - all good
Filled with 60oz and 8oz of oil(assumed that there was 1.5 in compressor and 1.5 in condenser)
COLD AS ICE.
3 days in use, it was 88 degrees and I'm sitting in the cul-de-sac waiting to pull into my garage and the pressure relief valve starts blowing refrigerant

Not that this is totally relevant, but this behavior has happened before. Prior to all that I described above the compressor grenaded and I followed that up with a complete rebuild of the system. (all new components top to bottom) and after I got everything up and running, the pressure relief valve started doing the same thing. So I evaluated everything, then the tranny went bad and it sat for 3 years. New R&R on the tranny, new dryer, and start over with my opening "Last week I blew out all the lines..."

Could this just be an issue where the fan clutch is not cooling enough because it's aftermarket? Could there be a blockage in the condenser somehow? Faulty expansion valve? It's hard to reproduce...it doesn't always happen the same way every time, but it always stops as soon as I turn off the A/C.

 

[Hamfisted]

What's your low and high pressure on the AC system ? You could just be overfilling it. Shoot for 40-45 degrees out of the center vents.




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[heuster]

What's your low and high pressure on the AC system ? You could just be overfilling it. Shoot for 40-45 degrees out of the center vents.




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Temp was reading 50 degrees. Can't go wrong on the math. The system calls for 62oz when empty and I only put 60 in it.

 

[Hamfisted]

Did you use a new condenser and put a good vacuum on the system ?

 

[heuster]

Did you use a new condenser and put a good vacuum on the system ?

did not use a new condenser and vacuum looked good and checked out great. If the condenser had a blockage, wouldn't it be blowing freon all the time? Usually when something like that happens doesn't the system work fine, it just doesn't get cold?

 

[heuster]

Any ideas on this? I am just not coming up with anything anywhere I look. I could start throwing money at it and replace the condenser and refill, then replace the compressor and refill...that's over 100$ worth of freon

 

[heuster]

Could really use some more ideas from anyone that is familiar with AC troubleshooting. I do have a couple videos I took, but the refrigerant level was a bit low from losing freon out the pressure relief valuve. Blew cold, around 60 degrees and didn't blow any freon while sitting in the garage idling for about 20 minutes.

 

[JamaicaJoe]

The above might give you an idea if there is too much refrigerant in the system. You might want to open all doors and run the AC fan to circulate ambient temperatures through the system. Note this is static pressure when the system is off, no suction on the low side so it will be higher than when system is running. Use a thermometer to get your ambient .

 

[heuster]

The above might give you an idea if there is too much refrigerant in the system. You might want to open all doors and run the AC fan to circulate ambient temperatures through the system. Note this is static pressure when the system is off, no suction on the low side so it will be higher than when system is running. Use a thermometer to get your ambient .

So the challenge I have with this is that I haven't added any refrigerant into the system since it started blowing freon out the first time and I was driving it the other day and it just started blowing freon again, even when it's on the low side already. How does that make any sense?

 

[JamaicaJoe]

Expansion valve getting blocked? Condensor coil dirty? Fan blade not turning?

 

[heuster]

Expansion valve getting blocked? Condensor coil dirty? Fan blade not turning?

Brand new fan clutch, recently new condenser, recently new expansion valve

 

[heuster]

Here are a couple videos I took - but the relief valve thing was not happening during this time unfortunately.

IMG_8108.MOV

drive.google.com

IMG_8109.MOV

drive.google.com

 

[Motorcity muscle]

As suggested the only way to know the system pressures while running is with gauges, safety valve could be faulty or saving your life.

 

[heuster]

I wish I could provide what you're asking, I just can't. It can't be recreated I can't cause it to happen and by the time I get my gauges on if it happens start doing it where I actually have them, all my refrigerant is going to be gone.

Is there anyone that can help to determine if this is happening, "X" is generally going to be the cause? (Like a blockage in the condenser, or a bad expansion valve) I don't know where to start and I don't want to replace everything. I'm trying to give you all the information I can.

 

[heuster]

**UPDATE** I had to do something. So, I installed a new condenser, dryer, expansion valve, orifice tube, and front manifold lines. Filled with 62oz of refrigerant and it's blowing at about 70 degrees. If I raise the RPMs to around 2k, it does come down to around 60 degrees. Low side pressure is 70, high side is 390 steady. Doesn't change unless I add RPM. At rest the system equalizes at 150. Compressor might have 2000 miles on it (Denso.)

Is there anything you can tell me with this info? I'm really tryin to get all the information together, but I need your help and experience. Please.

 

[Dobermans]

I recently replaced all my ac. I honestly can’t think off hand what it could be. My ac use to get warm without more rpm’s before I replaced it, it did that because it was low on refrigerant. But you just filled yours. Maybe check fuses, see if it’s throwing codes. I have read about people having problems with aftermarket fan clutch’s, but that would not effect your ac. Good luck I’ve been in those situations where you can’t figure out what’s wrong.

 

[Hamfisted]

**UPDATE** I had to do something. ... Low side pressure is 70, high side is 390 steady. Doesn't change unless I add RPM. At rest the system equalizes at 150. Compressor might have 2000 miles on it (Denso.)

Is there anything you can tell me with this info? I'm really tryin to get all the information together, but I need your help and experience. Please.

Both your Low and High pressures are way too high. You need 40-45 psi on the Low side and should see 200-250 on the High side. Let some gas out.

 

[Timo2824]

None condensables in the system, how are you pulling a vacuum? In the AC industry we pull a vacuum down to 500 microns, are you using a micron gauge?

 

[Motorcity muscle]

Relief valve is saving your life, 390# high side is dangerous. When gauges are attached, is the high side gauge needle steady? Assuming we are talking about your '01, only expy with 62 oz. charge and 11 oz of pag. So you added 8 oz's to a system that only holds 11 oz and already had oil in it. Proper procedure would be to drain and measure the oil in the compressor before replacing. Most of the oil charge lays in the bottom of the condenser and the compressor, when the system is off. There is no doubt you have way to much refrigerant in system with those pressures, how are you weighing in the refrigerant? What did you use besides air to flush lines? Air will not remove all of the oil.

 

[heuster]

None condensables in the system, how are you pulling a vacuum? In the AC industry we pull a vacuum down to 500 microns, are you using a micron gauge?

With an AC vacuum - it pulls down past 0 on the gauges and I let it run for about 45 minutes then let it sit for a couple hours and make sure the needle hasn't moved.