Compressor clutch locked on and gauges read the same

[casey_kreilein]

I recently bought a 2010 Corolla. The AC system does not provide any cooling from the ambient air. I finally got a chance to start diagnosing it yesterday and my immediate issue is the compressor is locked in the engaged position. The pulley is still spinning so it isn't damaging the belts. Before I popped on a new compressor I hooked up the gauges and both read 60 psi.

I'm thinking that something inside the compressor is faulty which is allowing it to spin without generating pressure. I also have only owned the car for the drive home of about 150 miles from point of purchase and I don't know if the previous owner tried to charge the system themselves.

I have a shop that will evacuate the system for me. My plan is to have them evacuate the system and then bring it back home to pull a vacuum on it to check for leaks. If I don't find any leaks I'll replace the compressor. Is it worth it to replace the condenser and the drier while I have everything open. Then I can go back to the shop to have them charge the system.

I'm wondering if there are any other checks I should do before I pull out the refrigerant, or if I'm way off on my thought process?

[JohnHere]

How many miles has your Corolla logged?

I recently bought a 2010 Corolla. The AC system does not provide any cooling from the ambient air. I finally got a chance to start diagnosing it yesterday and my immediate issue is the compressor is locked in the engaged position. The pulley is still spinning so it isn't damaging the belts. Before I popped on a new compressor I hooked up the gauges and both read 60 psi.

Let's see if my understanding is correct. The A/C clutch is stuck "engaged" and the engine (whenever it's running) continuously rotates the compressor mainshaft whether the A/C system is switched on or switched off—is that right?

Is the static pressure (engine and compressor not running) 60 PSI on both the high side and low side? Or, did you record those pressures with the compressor running? Also, what was the ambient temperature when you recorded those pressures?

I'm thinking that something inside the compressor is faulty which is allowing it to spin without generating pressure. I also have only owned the car for the drive home of about 150 miles from point of purchase and I don't know if the previous owner tried to charge the system themselves.

Do you know any of the history of service to the A/C system?

I have a shop that will evacuate the system for me. My plan is to have them evacuate the system and then bring it back home to pull a vacuum on it to check for leaks. If I don't find any leaks I'll replace the compressor. Is it worth it to replace the condenser and the drier while I have everything open. Then I can go back to the shop to have them charge the system.

I think you mean "recover" the refrigerant instead of "evacuate," which is the correct and proper way to proceed before the system is opened for any repairs.

Be aware that a system might not leak under vacuum, but it might leak under pressure—especially on the high side.

Typically, the manufacturers of a new or rebuilt compressors require that the condenser and Receiver/Dryer (R/D) be replaced at the same time to maintain the factory warranty on the compressor.

If the clutch is shot, and possibly the compressor, it's often cost-comparable to purchase a new clutch-and-compressor assembly.

The OE for the A/C system in your car is Denso.

[casey_kreilein]

There are just under 140,000 miles on the engine.

You are correct in that the compressor continuously rotates the mainshaft whenever the engine is running. The psi was with the engine running, but I did not record the ambient temperature but it was probably in the mid 80's based on the last couple days.

I have no idea about the service of the vehicle. The only thing I know is it was purchased by an elderly lady in 2017 who drove it until sometime in 2022 when she moved into a nursing home. I only know this because it was the last time the vehicle was registered. She passed last August and the heir sold it to me a couple days ago.

You are correct in that I used the incorrect term of "evacuate" instead of "recover. I have access to a Self-Help Auto Skill Center through the Army that has HVAC service equipment for Soldier's use.

Thank you for the info about the system leaking under pressure. Makes sense but it never crossed my mind.

I did some research today and realized I will replace the condenser and receiver/dryer as well.

Is there a way I can test the expansion valve to see if it needs to be replaced as well while I have the system open?

[JohnHere]

There are just under 140,000 miles on the engine.

Ahhh, just getting broken in

You are correct in that the compressor continuously rotates the mainshaft whenever the engine is running. The psi was with the engine running, but I did not record the ambient temperature but it was probably in the mid 80's based on the last couple days.

Sounds like both the clutch and compressor are shot.

When you remove the old compressor assembly, pour out some of the oil and inspect it. If it's amber in color and free from any "glitter" (metallic and/or plastic particles), you're good to go with a new compressor, condenser, and R/D. On the other hand, if the oil is black and full of particulates, that means the compressor has disintegrated internally, requiring that the evaporator and lines be thoroughly flushed.

If you can get to it, also remove the liquid line (the skinnier of the two) at the TXV. If you find desiccant beads that look like coarse sand inside, it means the desiccant bag inside the R/D has ruptured. That situation would also require the aforementioned parts to be flushed.

You are correct in that I used the incorrect term of "evacuate" instead of "recover. I have access to a Self-Help Auto Skill Center through the Army that has HVAC service equipment for Soldier's use.

Thank you for your service.

I did some research today and realized I will replace the condenser and receiver/dryer as well.

Great! But see above for additional information.

Is there a way I can test the expansion valve to see if it needs to be replaced as well while I have the system open?

There's no reliable way to test a TXV unless you have specialized equipment. If you have any doubts about its condition, it's best to just replace it, preferably with an OEM Denso part.