rattling noises and possible a/c compressor locking up

hedron · 10-31-2024, 02:08 AM

https://files.catbox.moe/1uj0ib.mp4

The above video, I believe, shows my a/c compressor locking up. Or is that just normal behavior? Because it looks like the belt is moving, but the compressor is not.

I think simply taking a knife and cutting the belt would be sufficient to solving the problem, for now. Cold weather has finally arrived (I nearly froze to death the other day on a hike not prepared for a temp drop from 55f to 20f) and I have no need for A/C until the spring. But maybe I'm wrong on the internals of the EJ25 engine, and something else needs to be done?

Also, at 0:22 there is a quite disturbing rattling sound that is eerily similar to a water pump bearing gone bad. I'm just asking because maybe someone knows it's just a normal sound and I should just not worry about it.

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Charlie-III · 11-01-2024, 10:13 AM

Engine running, the outer ring of the AC pulley spins. Turn on AC or defrost, the center part of the AC pulley locks to outer part and runs the compressor.

Noise.......I don't have a good sound to tell.

hedron · 11-01-2024, 01:35 PM

Quote:

Originally Posted by Charlie-III

Noise.......I don't have a good sound to tell.

A rattling noise clearly begins at :22 seconds of the video. I've been looking at "bad water pump" videos on youtube, and it sounds exactly like that. I had a previous car with a bad water pump and it sounded exactly like that. It could be one of the other bearings as well, since I don't have a stethoscope.

But you're saying the stop/go behavior of the compressor is normal? (for an ac and defroster that is set to 'off' position)

Charlie-III · 11-01-2024, 11:45 PM

What I posted on AC is correct, all(?) automotive AC compressors work the same way. It's an electromagnetic clutch. That's why there is a wire going along the compressor to the middle part of the pulley to power the magnet.
Defrost uses the AC to dry the air blowing onto the windshield.

My available sound sucks to hear your sound clip.

hedron · 11-02-2024, 12:29 AM

My last car, Toyota Camry, the A/C compressor locked up and snapped the serpentine belt. But with that vehicle, it constantly spins. The clutch is internal, and operates when activated, but the 'wheel' spins continously. When it locked up it wouldn't spin. I just assumed all compressor worked that way. I guess I'll check under the shroud tomorrow.

Charlie-III · 11-02-2024, 01:24 AM

Quote:

Originally Posted by hedron

My last car, Toyota Camry, the A/C compressor locked up and snapped the serpentine belt. But with that vehicle, it constantly spins. The clutch is internal, and operates when activated, but the 'wheel' spins continously. When it locked up it wouldn't spin. I just assumed all compressor worked that way. I guess I'll check under the shroud tomorrow.

If the internals of a compressor locks up for whatever reason, then yes, engaging the clutch with engine running will shock load the belt, likely breaking it.

hedron · 11-05-2024, 10:06 PM

Ok, upon further inspection, it seems the a/c compressor isn't locking up. It just operated differently than I expected.

But I'm not convinced that rattling is normal.

10-31-2024, 02:08 AM	#1
hedron Scooby Newbie Member#: 535911 Join Date: Oct 2023 Vehicle: 2011 Impreza 2.5l Pr	rattling noises and possible a/c compressor locking up https://files.catbox.moe/1uj0ib.mp4 The above video, I believe, shows my a/c compressor locking up. Or is that just normal behavior? Because it looks like the belt is moving, but the compressor is not. I think simply taking a knife and cutting the belt would be sufficient to solving the problem, for now. Cold weather has finally arrived (I nearly froze to death the other day on a hike not prepared for a temp drop from 55f to 20f) and I have no need for A/C until the spring. But maybe I'm wrong on the internals of the EJ25 engine, and something else needs to be done? Also, at 0:22 there is a quite disturbing rattling sound that is eerily similar to a water pump bearing gone bad. I'm just asking because maybe someone knows it's just a normal sound and I should just not worry about it. * Registered users of the site do not see these ads.

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11-01-2024, 10:13 AM	#2
Charlie-III NASIOC Supporter Member#: 30669 Join Date: Dec 2002 Chapter/Region: Tri-State Location: USA, North NJ, 07456 Vehicle: 1998 Legacy 2.5GT Silver Sleeper BK, 5MT	Engine running, the outer ring of the AC pulley spins. Turn on AC or defrost, the center part of the AC pulley locks to outer part and runs the compressor. Noise.......I don't have a good sound to tell.

11-01-2024, 11:45 PM	#4
Charlie-III NASIOC Supporter Member#: 30669 Join Date: Dec 2002 Chapter/Region: Tri-State Location: USA, North NJ, 07456 Vehicle: 1998 Legacy 2.5GT Silver Sleeper BK, 5MT	What I posted on AC is correct, all(?) automotive AC compressors work the same way. It's an electromagnetic clutch. That's why there is a wire going along the compressor to the middle part of the pulley to power the magnet. Defrost uses the AC to dry the air blowing onto the windshield. My available sound sucks to hear your sound clip.

11-02-2024, 12:29 AM	#5
hedron Scooby Newbie Member#: 535911 Join Date: Oct 2023 Vehicle: 2011 Impreza 2.5l Pr	My last car, Toyota Camry, the A/C compressor locked up and snapped the serpentine belt. But with that vehicle, it constantly spins. The clutch is internal, and operates when activated, but the 'wheel' spins continously. When it locked up it wouldn't spin. I just assumed all compressor worked that way. I guess I'll check under the shroud tomorrow.

11-05-2024, 10:06 PM	#7
hedron Scooby Newbie Member#: 535911 Join Date: Oct 2023 Vehicle: 2011 Impreza 2.5l Pr	Ok, upon further inspection, it seems the a/c compressor isn't locking up. It just operated differently than I expected. But I'm not convinced that rattling is normal.