Automotive Air Conditioning Information Forum

Hello,

I have a 2011 Equinox in which the AC recently stopped working. It started up one day and I heard the belt screeching for about 60 seconds and then the noise went away and the AC no longer worked. Inspecting further, the AC lines still have pressure (still has Freon in the system using gauges), the low pressure switch is working correctly as clutch still engages but the compressor is not running. The center section of the pulley still spins freely as well. I can make the clutch engage by passing the relay, when engaged there is no drag on the engine (rpms do not change).

Seems like the clutch is the issue and possibly not the compressor, please let me know your thoughts or what else I can do to verify what is wrong?

Thanks in advance for your comments!

gjrobinson68 wrote: ↑Mon Apr 18, 2022 8:30 am ...the low pressure switch is working correctly as clutch still engages but the compressor is not running. The center section of the pulley still spins freely as well.

Doesn't the compressor actually run if the center section of the pulley (attached to the compressor's main-shaft) spins freely? But perhaps it spins a little too freely, indicating that the compressor seized, for whatever reason, and the seizure caused something to break internally and the main-shaft to freewheel.

Thanks for the reply,

Yes, I think the compressor has failed, the center section rotates very easily with the engine off. I don't have a lot of experience with AC compressors and how they fail, was hoping it could be just the clutch is no longer engaging and maybe it needed to be shimmed for the proper clearance. Is it possible for the compressor shaft to break internally and still spin as well has hold pressure? How easily should a compressor spin by hand?

Thanks again for your help!

Your description, including the screeching, seem to indicate the comp seized, and the continued rotation of the clutch sheared the shaft.
The center section should not turn totally freely, there should be some resistance. If you have access to another car, you can try to turn the center section on that car and compare. Engine off of course. Pretty much what JohnHere said.

You may very well be facing a sizeable repair. If you don't have much mechanical experience, this would call for a pro.
You will need, in addition to a new comp, a new condenser, and other parts. Also a darn good flush of the hoses and evaporator. The entire system is most likely contaminated with fine metal particles from the failing comp.

Had any work ever been done on the system? Any refrigerant added because of a leak? The comp most likely ran dry of oil. How many miles on the car?

Try to find a shop that is MACS certified, these guys are the best

Thanks tbird,

It is the original compressor, the system has not been touched in since new (2011). Just turned 130K so a compressor failure is likely the issue.

I have considerable automotive experience but I have not gone through the process of repairing an AC system before but I would like to try, I have rebuilt complete engines and transmissions, restored cars, etc. so I would enjoy learning the process. I have the gauges, will need to buy a vacuum pump. The flushing part is where I could use some advise from a DIY standpoint, I assume this is step with the most risk for a future failure. I have not searched the site yet, are there any tutorials for the DIY'er?

Thanks again for your comments.

Yes, indeed, DIY flushing is the hard part. A professional flushing machine is hands down the best way to go, such as made by HECAT. But it is pricey. Using the small and pricey cans of flush from the auto parts store is seldom adequate. Please note that a condenser cannot be flushed, it must be replaced.
I suppose you could remove each hose and flush with store flush and dry high pressure air such as you would get from a bottle of dry nitrogen. Flushing the evap will be harder. Your dryer and TXV should be changed out.

You might try searching under flushing on this forum.
I am not at the moment able to think of a good source of instruction on everything you need to do. Please note that mobile AC work is very different from overhauling an engine. I do both, and they are not similar at all.
Be careful of youtubes. They are seldom fully accurate from my observation. They commonly miss a step or two here and there. I suppose you could watch several of them and compare the information.
You could also do a search here, it may be written up.

A really good way to educate yourself on mobile AC is to step back thru the archives here and read each and every problem and the solutions posted by the experts. There are some real hot shots here, like nowhere else.

Avoid using compressed air, it has moisture in it.

TIM, is there a DIY flushing and/or charging procedure in the archives?
I do not have time to look, will look later

There is no compressor I have ever seen that can lock up internally and still seem to have a shaft that spins freely. This compressor appears to be a fixed swashplate Delphi, and I've never opened up one if these, but I highly doubt any compressor could fail like that.

If you hook up high and low gauges and spin the clutch center by hand, do you see the needles making small jumps?

OK, Detroit is a sharpshooter, and works in the industry.
Do this:
1. try what he says
2. Locate a compressor on another car and try to turn the center section and get a feel for the resistance

report back

The screech and the fact that the clutch when engaged will not load up the engine are not good signs to me.
But try the above before you start ripping stuff apart

Here is a link to the charging procedure.

https://www.autoacforum.com/messageview ... eadid=7931

Here is a link to a good discussion of flushing and a flusher made by HECAT who makes good stuff

http://65.36.189.119/messageview.cfm?ca ... SGDBTABLE=

Thanks guys for your thoughts, I will try the items you suggest and get back to you. Probably this weekend, as DetriotAC knows it decided to snow here in SE Michigan this week, the weekend looks warmer.

I was convinced the compressor was shot until I jumped the clutch relay and it did not stall the engine. I then noticed the clutch was pulling as it should with the engine running but compressor is not putting a load on the engine so I starting to think it might be just the clutch?

I will report back as soon as I can, thanks again for your support!