Posted: 4/28/2026 7:09:40 PM EDT
[Last Edit: Snert][Edited]
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Ok Gents, I have a 5th gen Ram 1500 5.7L E-torque with a A/C issue. End of the summer the AC was acting a bit wonky. Sometimes it worked, sometimes it did not. Any way had dealership take a look, they said the refrigerant was low. charged it back up and it worked for a day. They said the hi side shrader valve had a slow leak. Winter was just around the corner and I decided I'll wait till spring. Well heater core started leaking and local shop did the core. When they went to recharge the A/C system it would only take 1/2 the refrigerant. They said the compressor is bad, they are getting the same pressure readings on both the hi and low side lines. Basically saying one of the valves in the compressor is not closing. Does the compressor theory sound legit? I don't want to invest in a new compressor to find out its a 30 dollar switch. At this point between the dealership and while local private shop i have conflicting diagnosis. **UPDATE 5/27/26.. Truck was due for inspection, off to the dealership it went. Explained the AC issue and asked them to look at it. They evacuated the system and tested for leaks, found nothing. They then charged the system back up and then found a leak... There was leak dye on the expansion valve right top corner. Now when the heater core was done I provided all the parts, but did not get the new seals for the expansion valve. Had the dealership completely discharged the system. I will change the expansion valve, o ring seals between it and the evaporator. I will also replace the metal seals on the end of the lines that attach to the expansion valve. Already have a appointment for Friday to recharge the system... Hopefully this is the final answer... And when the recharged just before finding the leak. They were able to get a FULL charge of refrigerant to go in to the system. |
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OH, USA
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The compressor likely will NOT run and compress if it’s only half charged as the shop said. There are pressure switches that need to read enough pressure prior to completing the circuit to activate the compressor. As to why it would only take half a charged, that’s strange. A 2019 Ram is a 1234yf refrigerant vehicle and there really isn’t a short cut using a machine to charge it. That refrigerant pays 1.4 hours for an evac and recharge because you can’t shortcut it. I would start by pulling the charge and trying again, charging on both the high and low sides. I wonder if they plugged the expansion valve with something when removing the hvac box and left it in, or if dirt or debris got into the valve while they had it apart. Just curious what they charged for a heater core job? I do a bunch of them and that coolant is pure trash Ram puts in their vehicles. Attached File |
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Originally Posted By Realdealoo8: The compressor likely will NOT run and compress if it’s only half charged as the shop said. There are pressure switches that need to read enough pressure prior to completing the circuit to activate the compressor. As to why it would only take half a charged, that’s strange. A 2019 Ram is a 1234yf refrigerant vehicle and there really isn’t a short cut using a machine to charge it. That refrigerant pays 1.4 hours for an evac and recharge because you can’t shortcut it. I would start by pulling the charge and trying again, charging on both the high and low sides. I wonder if they plugged the expansion valve with something when removing the hvac box and left it in, or if dirt or debris got into the valve while they had it apart. Just curious what they charged for a heater core job? I do a bunch of them and that coolant is pure trash Ram puts in their vehicles. https://www.ar15.com/media/mediaFiles/329336/IMG_3123_jpeg-3755503.JPG Charged $1100 for just the labor, I provided the parts. If I recall correctly, they tried charging the system 2 times. He said both the high and low side had the same pressure. A few years ago 8 hit a deer dead smack in the middle of the grill. Bent the condeser/trans cooler but did not leak. It was replaced with OEM parts. A dealership charged the system and it was fine until last fall. That's when it started acting up and my local dealership said the schrader cores were leaking. The shop that did the heater core swapped out the shrader valve cores with oem ones I provided. |
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Originally Posted By Snert: Charged $1100 for just the labor, I provided the parts. If I recall correctly, they tried charging the system 2 times. He said both the high and low side had the same pressure. A few years ago 8 hit a deer dead smack in the middle of the grill. Bent the condeser/trans cooler but did not leak. It was replaced with OEM parts. A dealership charged the system and it was fine until last fall. That's when it started acting up and my local dealership said the schrader cores were leaking. The shop that did the heater core swapped out the shrader valve cores with oem ones I provided. Both sides will have the same pressure when the compressor is not compressing it equalizes out. Still strange they say they could not completely charge it, I have no problem filling a system completely without using the compressor to assist. I would find another family owned shop and have them take a look. Wish you were close because I’d fix it right up for you. |
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so it has a movable swash plate to change the amount of compression it has based on load. if that goes out then you don't get any pressure difference either. I think some scan tools have the function to change the angle. but just curious if they ruled that out as a problem? |
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Going to see if I can get the compressor tested via scan tool. I have Alfaobd and the security bypass cable. Just have to figure out if it will test the solenoid to change the plate angle. I will figure if I can test it and it fails, new compressor will be in order. This is new territory for me to figure out. |