Automotive Air Conditioning Information Forum

I am working on a 2012 Dodge Caravan. The initial problem was a bad AC clutch. I changed the compressor, dryer and the front expansion valve. The issue now is after putting in a little over a can of 134a about 12 ounces or so, the low and high side gauges are reading 80 psi. The compressor is running steadily and not disengaging. While it's running the pressures on the either side don't move. The air temp. is also not cold. Since this has an expansion valve in the rear could this be bad causing this? I'm really confused as to why the compressor runs but the pressures don't move and I can't get any more 134a into the system. I'm guessing the can pressure and the system pressure have equalized .

Are you certain the couplers are actually engaging the gauge ports? I seem to have to fiddle with couplers all the time.
I think you are just reading can pressure

Is compressor shaft itself turning? Or just the pulley

How good was your vacuum

If it was the coupler I don't think I could pull a vacuum on it then. As far as the shaft turning, how can I tell? The clutch is engaged, that much I can see. You're right though it does seem like can pressure. I called the parts store and I can't get a replacement for it until early next week.

Just for kicks,
Close the shutoff knobs on your couplers. Remove the lo side hose from your manifold, and leave it free. Then crack the coupler shutoff knob on the lo side just a tiny bit for a short period to see if any refrigerant is released. If not, your couplers are not fully connected for some reason. I have high quality couplers, but everything is made of chinesium now, even the name brands like Robinaire, and performance can be sketchy

I have had errant pieces of rubber from nowhere act as as flap valves inside the ends of my knurl knobs. Anything can happen

Sounds like the shaft is turning if clutch is engaged

You're getting away from the issue some. The compressor clutch doesn't disengage and it's not cooling, beside the pressure reading issue.

Septaric wrote: ↑Thu Jun 17, 2021 7:26 am You're getting away from the issue some. The compressor clutch doesn't disengage, and it's not cooling, besides the pressure reading issue.

With limited information, not being there to check.

If the internals of the compressor is turning. You have a defective compressor/broken shaft. The blockage would send the high side way up and shut things down. You need to confirm the shaft of the compressor is turning. Maybe even reclaim refrigerant, remove the suction hose at the compressor. Spin clutch hub but and see if you get suction at the suction port of the compressor.

I have to put this van back into service. They need it tomorrow. I guess I will have to wait for the replacement compressor to come in. Thanks for the input guys.

If undercharged how can it cycle and cool

Exactly! But the clutch was engaged. I found the high pressure switch on the dryer and unplugged that and plugged it back in and the clutch released and engaged when I unplugged it and plugged it back in. Like I said it confused the hell out of me.

Does the clutch ever cyle off? With low refrigerant, it should unless pressures stay static because the compressor is not working/turning.