Air con noise - is it my clutch or compressor

[Gilera]

Hi. I have a 2006 Toyota Estima/Previa import with 3.5L 2GR-FE engine. The air con works fine but recently a bad noise started to come from the compressor. It only happens when the AC is engaged. I rang a local AC workshop and the guy said if it makes the sound only when the AC is switched on the compressor will need replacing. This is not what I had read and was wondering if the clutch might have been just on the verge of slipping.

I took off the front wheel and splash guard to take a look. I took off the serpentine belt and the pully spins freely. Turning the clutch plate felt uniform - no weird sounds or roughness. I checked the clutch air gap. It was about 0.65mm or 25 thou. I couldn't find the exact specs for this model but figured that this is at the upper end for most models. I took the clutch plate off and found only 1 shim which was about 1.0mm thick. It looked identical to an M6 washer. Without the shim there was no air gap so I took a regular M6 washer and filed it on a flat file until it was about 0.7mm thick. Put it back together and it still makes a small sound but is much better. I need a better solution as even though I was careful, the air gap is not exactly the same all around the clutch plate at different points, I guess due to the shim not being exactly flat.

When I had the clutch plate off I notice that there was a ring that was shiny and the rest wasn't. Is it possible to tell from the pictures whether the clutch has been slipping? Is it worn out? It is a lot cheaper to replace the clutch on these than the compressor so hoping it is the source of the issue.

https://imgur.com/a/PqcN2qR

Here is a video of the sound it was making
https://imgur.com/a/P8Ap373

[Cusser]

I'm not an AC professional.

I don't like the noise.

If mine, I'd use chalk or paint, and make a line on the drive plate (center part) and on the pulley edge to try if I could determine that the AC clutch is slipping sometime.

When the AC clutch slipped on my Frontier, it didn't make noise, the drive plate just stopped turning intermittently, and on that I was able to fix by removing an AC clutch shim.

[Gilera]

Great idea about the line on the clutch and pulley thanks. I guess if the clutch is not slipping than the most likely explanation is the compressor failing. Just strange that reducing the thickness of the spacer had a big impact on the noise if its not related to the clutch.

[JohnHere]

How many miles on your Previa? And to your knowledge, has the A/C system ever been worked on?

[Gilera]

Its a Jap import but came with supporting paperwork to show kms. 105000km currently (about 60000 miles). No service history so unsure of any previous work. I do know that the clutch plate bolt and clutch plate came off very easily and looked like there was some light oil on the splines but appears all original otherwise.

[JohnHere]

Instead of taking a chance on replacing only the clutch, which costs about as much as a complete compressor-and-clutch assembly, I suggest replacing the compressor assembly. I believe the original equipment is Denso for your van.

If you do the job yourself, drain the oil from the old compressor and examine it closely. If the oil looks very dark to black and/or contains metallic "glitter" and plastic particles, this indicates that the compressor is beginning to disintegrate internally. If that's the case, then you'll have more work to do and additional parts to replace.

By that I mean you should also replace the condenser, possibly the TXV, and of course the receiver/dryer, along with any lines or hoses having integral mufflers (can-like devices), and solvent-flushing the rest. The idea is to start with a 100-percent clean and dry system before installing the new components. This is very important, particularly to maintain the warranty on the new compressor assembly and to ensure that the system will continue working indefinitely.

It goes without saying (but I'll say it anyway ) that all seals and o-rings must be replaced, a thorough evacuation must be performed, pure R-134a refrigerant and PAG-46 oil (the double-end-capped variety is preferred) should be installed according to the manufacturer's specifications, and a final leak-check should be completed using an electronic leak detector ("sniffer").

[Gilera]

Sounds like very good advice thanks!