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Noise in serpentine belt area

3206 Views 13 Replies 3 Participants Last post by  timebuilder
Hi, I have a 1988 Camry with a whining noise coming from the serpentine belt area. I think its either the AC or Alternator bearing going bad. Is it hard to change the bearing in the AC, and can it be done without draining the freon? Also if its the AC can I just buy a serpentine belt thats designed for the camry without AC, if I deside not to fix the bearing?

Any input is much apreciated
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The car is equipped with a V-belt. A serpentine belt is a long, flat belt with longitudinal serrations that snakes its way around all accessories, using both the inside and outside of the belt to bear against rotating surfaces.

Before you take any action, you need to find the true source of the noise. For example, I have worked with literally hundreds of AC compressors, and not one ever had a bearing noise. HOWEVER, very close to both the alternator and the AC compressor is the water pump, and they have a HABIT of creating interesting noises.
I thought it was called a serpentine belt because the auto parts store called it that. Thanks for the clarification.

I ran the car idle without the v-belt for a minute and the noise wasn't there anymore. Do you think its the alternator then?
It could be.

When the belt is installed, does the quality of the noise change with

1) the ac turned on or

2) extra electrical load (blower, lights on high beam)?

When you turn the aternator pulley, do you feel any uneven drag or "texture" as the pulley is turned?
The noise goes away when the AC and the two fans in front are on. When just the AC is on with out the fans spinning, the noise is alot less audible but there none the less.

I'm not sure how to turn the pully on the alternator with the belt on. I tried by pulling on the belt and by turning the pully by hand but it didn't move.
I should have been more clear.

I meant turning the alternator pulley with the belt off, to feel for imperfections in the bearings. Some times you can feel brinnelling of the races.

From the way you described the way the noise goes away with the ac on, it could be the ac clutch bearing.

Since I can't make a close-up determination, you may want to have a local guy give a listen.
Ok, I'll take the belt off and try to feel for inperfections. Thanks for always responding quickly.
Hey, you're lucky there's nothing good on TV anymore, LOL!

With the belt off, you can do the same "feely" routine with the ac clutch. Rotate the pulley and see if it feels smooth.
One more thing:

while the compressor bearings have never gone bad on me, the comprersssor clutches have sometimes needed replacement. The clutch/pullley assembly has its own bearing, separate from the compressor bearing.

The entire clutch/pulley assembly can be replaced on an AC compressor without disturbing the refrigerant charge in the system. The compressor bearings would not be seriveable, and you would instead replace a compressor that had bad bearings. That compressor replacement procedure WOULD require the evacuation and recharge of the system.
I was looking up the clutch bearing in the gen2 service manual and saw how the bearing is in the clutch. If the clutch bearing is the problem can I just unbolt and replace the clutch as a unit instead of taking it apart to get to the clutch bearing?
At most parts stores you can buy a stethescope for checking noises. Cheap method is to place a screwdriver near the bearing and listen with your ear next to the handle.
superfob said:
I was looking up the clutch bearing in the gen2 service manual and saw how the bearing is in the clutch. If the clutch bearing is the problem can I just unbolt and replace the clutch as a unit instead of taking it apart to get to the clutch bearing?
Although most compressors are similar, you would have to see what is available. I'd expect the clutch/pulley assembly would be replaced as a unit. Perhaps you could find one at a yard.

Make sure you are correct in your diagnosis. I have an entire tool drawer devoted to ac service, and you may need a specialized tool just to take the assembly off the shaft of the compressor, and I doubt if a parts store would have one to lend out.

Another method to listen to noises is a 3' length of 3/8" fuel line, held up to the ear and placed in the suspected noise area.
Autozone sells rebuilt AC clutches for $50 online and they lend out AC tools in store. I'm just not sure if what they lend out is compatible with my AC clutch. I gonna go check and see.

I tried the screwdriver method and it seems to be the coming from the AC clutch bearing. I would try the fuel line method but I don't have any available.

The noise goes away when the AC's on so I've been driving around with in on.
Nice going. I would say that if the noise goes away when the ac is on, you have found your problem. That's not 100%, since the added load on the belt by the ac compressor could be changing the dynamic for other parts. The clincher is being able to locate the noise as being in the compressor clutch area.

When the clutch is engaged, the entire assembly rotates as a unit, and both the inner and outer races of the bearing move at the same speed.

Make sure you compare your assembly with the replacment. You want to have the part with the bearing (there are several clutch parts available) so make certain you have what you need before you leave the store.

As for doing the job, be very careful. You will need to either do this job from below or above, but either way you may have to remove the bolts that hold the compressor to its bracket. Be carful to not put a lot of exrtra stress on the hoses by twisting or dangling the compressor by the hoses. So, support the weight of the compressor to take the weight load off the hoses. If you have room, do it with the compressor in place. Not very comfy, but it's better to not disturb old hoses.

Wear safety glassses or a clear face shield in case the refrigerant escapes. At minimum, you could get a freeze burn on your skin, but it can be much more serious, such as a frozen eyeball, inhalation injury, or even the creation of poisonous phosgene gas if there is a flame nearby. No lanterns that have a flame, or even garage furnaces running!

Finally, make sure you have the right air gap at the clutch magnet. Unless the parts man can tell you it is correct from the factory, check it with a feeler gauge and adjust it using shims. If you don't have a feeler gauge, you can estimate the gap using an object that fits the gap on the old clutch, and adjust it until it is correct.
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