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squeeling chirping AC

Posted by andre_media (My Page) on
Tue, Jun 3, 14 at 15:42

Toyota Sienna

When starting up it give a tiny chirp, sound like squeaky/slippling belt. But when I turn on the AC the squeeling becomes much louder and worse. If I turn off the AC the noise stops. Then when the car warms up, you can have the AC running without the bad noise with only an occasional chirp.

What does this sound like? Belt, Bearing, Pulley.

Is there an easy way to check?

Thanks Much

Follow-Up Postings:

RE: squeeling chirping AC

Sounds like a worn or loose belt. the AC compressor pulley has a clutch. It spins easier when the clutch is not engaged. when you turn the AC on the clutch engages and the resistance to turning is much greater...hence the squealing gets worse.

RE: squeeling chirping AC

Thanks,,, does it makes sense that when the car is fully warmed up (5 mins of driving or so), the noise almost completely goes away?

RE: squeeling chirping AC

My guess goes to belt slip when the compressor clutch engages.

The belt may slip from not enough tension or wear. In the olden days, the compressor was driven by a single V-belt. Your belt may have multiple, small v(s) running on a matching sheave. When new, only the sides of the Vs touch the sheave and friction grip is good. As the Vs wear down, the belt back can come in contact with the top of the sheave and reduce the load on the V-sides. This reduces the amount of torque the belt can transmit and it slips.

With the old, single-V belt, the belt was servicable until it sank far enough into the sheave to come in contact with the bottom of the groove. At that point, its grip diminishes. It should be replaced before it wears this much. The rule of thumb for the single-V belt was to replace when the top surface of he belt became even or below the top edge of the sheave.

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