Automotive Air Conditioning Information Forum

1999 Dodge Ram, thanks for the help with this. Ac had been great since I changed the pump 10yrs ago until this spring. Quits working, top it off with a can at home and it keeps going. Finally got worse and I put some dye in it and lost pressure within 24 hrs. But I found the seals on the compressor leaking so I got a seal kit and took it to work and hooked up to our machine to recover. Thinking I would only pull a little out I pulled almost 2.7lbs out. Wth? It's only a 2lb system! Put the new seals in, pulled a vacuum and put 2lbs back in. Nothing, put another .2 in and the compressor would cycle a little but now I'm seeing 100-150 on the low side and 100 on the high side on the machine. Decided to stop at this point until I have a plan, and here I am. Help?

Also I only got .5oz of oil from the recovery, I tried adding more to the compressor but it wouldn't take any. I have the Cummins and the ac compressor sits at the bottom of the engine, meaning where the seal was leaking was the low point of the system. Thought I might have lost some oil and from this.

Ambient? Vacuum for how long? What type of pump? Electric? Need working pressures at 1500 RPM with a properly charged system.
Low cannot be higher than hi.
Those pressures almost seem like the couplings are not depressing the valve core, they seem more like static readings.
I suspect you will have to recover, flush entire system, and dry thoroughly. Especially since comp is low riding. Check the OT for debris just in case. Suspect you have topped off before. Topping off seldom works.
Then go from there.
What is status of fan clutch? They wear out.

Robinair 34288NI, 75 degrees, fan clutch will hold a shop rag up, didn't have a helper to check 1500rpm, the low wasn't higher I guess (just had the appearance with the different scaling of gauges). Do pressure switches go bad ever requiring more pressure?

Nrose07 wrote: ↑Sun Jun 12, 2022 10:44 am Thinking I would only pull a little out I pulled almost 2.7lbs out. Wth? It's only a 2lb system!

Two pounds net weight is the specification that I have for your truck as well, plus 8 fluid ounces of PAG-100.

Nrose07 wrote: ↑Sun Jun 12, 2022 10:44 am Put the new seals in, pulled a vacuum and put 2lbs back in. Nothing, put another .2 in and the compressor would cycle a little but now I'm seeing 100-150 on the low side and 100 on the high side on the machine.

Presuming the compressor is good, it sounds like the orifice tube might be missing. I believe this is a CCOT system, correct?

Nrose07 wrote: ↑Sun Jun 12, 2022 10:51 am Also I only got .5oz of oil from the recovery, I tried adding more to the compressor but it wouldn't take any. I have the Cummins and the ac compressor sits at the bottom of the engine, meaning where the seal was leaking was the low point of the system. Thought I might have lost some oil and from this.

If you think you might have lost some oil from the compressor, it's sheer guesswork as to how much, but I would reckon a small amount. This plus the 1/2 ounce you recovered, putting back a total of one ounce into one or more of the components seems like a fairly good guess. If the compressor won't take any, try putting some in the condenser and/or accumulator. Of course, the only way you'd know exactly how much oil it has is to start with a completely dry system.

Nrose07 wrote: ↑Sun Jun 12, 2022 2:39 pm Robinair 34288NI, 75 degrees, fan clutch will hold a shop rag up, didn't have a helper to check 1500rpm, the low wasn't higher I guess (just had the appearance with the different scaling of gauges). Do pressure switches go bad ever requiring more pressure?

An ambient of 75F is a bit low for system testing. I prefer 85F minimum.

The fan clutch might appear okay, but viscous drives usually last only two to three years. I'd replace it.

You'll need to measure the pressures with at least a 1,500-RPM engine speed for meaningful diagnosis.

And yes, pressure switches can go bad. With two pounds of refrigerant in the system and the compressor not running, the HPCO switch should be closed, which can be verified with a VOM.

Also be mindful of tbirdtbird's questions and suggestions.