Chirping noise under the hood

Tiny
RON CONWAY
  • MEMBER
  • 2008 LEXUS RX 350
  • V6
  • 2WD
  • AUTOMATIC
  • 198,000 MILES
Had a water pump and serpentine chain replaced. Two months later the air conditioner compressor was replaced. Now making tweeting type sound when first started in morning, seems to go away after that.
Thursday, April 21st, 2022 AT 11:18 AM

3 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Hi,

Chances are the serpentine belt is either loose or contaminated.

First, with the engine off, open the hood. Inspect the belt for anything that may cause it to slip. For example, engine oil or coolant may be on it.

If the belt is clean, confirm it is tight.

If the belt is tight and clean, there is a chance the idler pulley is failing. There was actually a service bulletin related to this. Apparently, these vehicles have faulty idler pullies that fail and squeak.

An easy way to determine if it is the belt or idler pulley is this. Get a small cup of water. Start the engine. Make sure to wear old clothes and safety glasses.

With the engine pour a small amount of water on the pulley. If the sound changes, then the belt or tension is the issue. If there is no change, it is likely the idler pulley

I attached a pic below with the belt routing.

Let me know what you find or if you have other questions.

Take care,

Joe
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Thursday, April 21st, 2022 AT 5:31 PM
Tiny
RON CONWAY
  • MEMBER
  • 2 POSTS
Hi Joe,

Unfortunately, I'm scheduled to return (drive) to New England on Saturday. Is it safe to drive it there and have it serviced then? Should I be concerned?
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Thursday, April 21st, 2022 AT 6:23 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Hi,

Without knowing exactly what the problem is that is a tough question to answer. How far is the drive? Is it possible for you to record the sound and upload it for me to hear?

By chance, did you try the water test I mentioned?

If the belt is loose or damaged, it could come off. That would prevent the A/C from working, the alternator from charging, the water pump from cooling the engine, and loss of power steering. If you could record it for me, I may be able to tell. If it is just the noise from the idle pulley and isn't too loud, it should be okay.

Let me know. Also, I'm listing things that could happen and not to worry you. If I didn't tell you, I would feel terrible if something happened. I hope you understand.

Let me know what I can do to help.

Joe
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Thursday, April 21st, 2022 AT 8:47 PM

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