AC Compressor Bearing Noise ONLY after turning AC off

[100s]

On my 02, I have noticed that if I turn the AC on and drive for a while I get a bearing like failure noise but only when the compressor cycles off. It will go on for a while once it's cycled off or I've turned the AC off. It looks a bit like the magnetic clutch is moving a little bit. If I don't ever turn the AC on, no noise. Is this the magnetic clutch going out on me?

AC still works great.

Thanks.

 

[excessive]

i had the magnetic clutch fail on my 98 at about 305k miles. I was able to swap out the magnetic clutch without even removing the compressor from the vehilcle. I found a new old stock OEM complete clutch unit on ebay and it was cheaper and easier than swapping out the compressor. A surprisingly easy repair.

 

[2001LC]

Easy way check or confirm, AC magnetic clutch bearing going bad. Remove serp belt and spin AC clutch pulley by hand. Any sound, bearing is on it's way out.

When replacing magnetic clutch, which houses the bearing. It's important to snap rings in proper orientation (beveled side). Also, we need to check and set clearance (air gap), within proper range.

Painting tips/holes of snap rings, before removing. Helps align snap ring pliers in holes, and once snap ring off and out. Paint marks, makes seeing orientation (bevel side out) on snap ring, easier.
Note: Bevel on inner edge of snap ring

Toyota sell a pack of shims. They're used to get proper gap. I had issue, both on 100 & 200 series, getting proper gap. I've had to grind/sand down to make thinner, one of the shims. From now on. I'll order two packs of shims to come up with more combos.

All videos and pictures below. Are pictures of 200 series AC. Which is similar to the 100 series.
100 series, torque 9ft-lbf.

Checking air gap:
I run a jumper from battery positive post. To the pin, inside single wire housing block, that comes from clutch. A second jump from body of AC compressor to negative battery post.



I've not tried, just replacing bearing. Likely bearing old/new, can be pressed out/in.
200 series magnetic clutch bearing

 

[styran]

i had this issue on my tundra, but they are all the same. you can either by a new clutch assembly from the dealership, or just press out and replace the bearing with an OE japanese one. I choose the latter for $30, although looking at it now, I would've replaced the entire clutch, as its old anyways. I will likely be back to replace the entier clutch assembly in the next 100k miles

 

[100s]

Easy way check or confirm, AC magnetic clutch bearing going bad. Remove serp belt and spin AC clutch pulley by hand. Any sound, bearing is on it's way out.

When replacing magnetic clutch, which houses the bearing. It's important to snap rings in proper orientation (beveled side). Also, we need to check and set clearance (air gap), within proper range.

Painting tips/holes of snap rings, before removing. Helps align snap ring pliers in holes, and once snap ring off and out. Paint marks, makes seeing orientation (bevel side out) on snap ring, easier.
Note: Bevel on inner edge of snap ring
View attachment 4150076
Toyota sell a pack of shims. They're used to get proper gap. I had issue, both on 100 & 200 series, getting proper gap. I've had to grind/sand down to make thinner, one of the shims. From now on. I'll order two packs of shims to come up with more combos.

All videos and pictures below. Are pictures of 200 series AC. Which is similar to the 100 series.
100 series, torque 9ft-lbf.
View attachment 4150078
View attachment 4150080
View attachment 4150081



I've not tried, just replacing bearing. Likely bearing old/new, can be pressed out/in.
200 series magnetic clutch bearing
View attachment 4150084

It looks like you are able to check the air gap with the compressor on the vehicle, can you point me to this process? I have a dial indicator etc. I'm also not clear on what was going on with the indicator plunger in the beginning. Thank you.

 

[styran]

It looks like you are able to check the air gap with the compressor on the vehicle, can you point me to this process? I have a dial indicator etc. I'm also not clear on what was going on with the indicator plunger in the beginning. Thank you.

the FSM has this procedure. honestly, if you're certain its the compressor clutch, just go buy a new clutch assembly from toyota, new snap rings. buy a snap ring plier kit from HF (ICON brand). remove skid plate, belt, youll be done in a couple hours. no need to touch AC system. its probably worn out, and if it isn't you already going to spend all the labor to get there. youll use the procedure and dial indicator to set the spacing. youll use the washers to do that. doable in the car. you can remove the oil filter if you want, thatll make it easier. i didnt and it was fine

 

[2001LC]

It looks like you are able to check the air gap with the compressor on the vehicle, can you point me to this process? I have a dial indicator etc. I'm also not clear on what was going on with the indicator plunger in the beginning. Thank you.

Checking air gap:
I run a jumper from battery positive post. To the pin, inside single wire housing block, that comes from clutch. A second jump from body of AC compressor to negative battery post.

I was just taking play out of dial gauge, in those first taps with needle moving.

 

[100s]

Finally had time to remove the belt, the AC pulley feels fine, it doesn't spin super easily, but also doesn't make any noise. Put a stethoscope on the AC housing and while turning the pulley no odd noise.. but I can't give it a "wheel of fortune" spin. But same goes for my idler etc, they are all relatively new so the bearings are tight, it spins like one of those.

Any tips on the clutch kit? I'll probably just replace all if it if I'm going be in there anyway. 2002.

thanks.

 

[Otis]

I had very similar symptoms that you noted in your first post and convinced myself the noise was coming from a failing AC clutch bearing so I went ahead and replaced it, which did not solve the problem. Turns out my alternator failed less than a week later and the noise was actually coming from it. You may not have the same problem I did but maybe worth also checking the alternator.