Question Noise at Idle

[JJVG]

I just had the C5 out for a burn. Idling at a light, there seems to be a higher pitched noise above the normal engine sound. I hear it clear from inside the cab. Pop the hood and it's harder to hear but sounds like its coming from the intake and louder as you get closer to the firewall. It seems to go away as I raise the rpm's. Any ideas?

 

[henkz06]

It could be one of the pulleys or the belt.

 

[Rruuff Day]

Sounds like an idler pulley bearing.... Hopefully not an alternator or power steering bearing...

 

[JJVG]

Well I just replaced both belts and all the pulleys except the harmonic...... last May. So I'm ruling out belts or pulleys. Keep up the troubleshooting it is helpful. I'll let you know if the sound was a one off noise. I hope so!

 

[JJVG]

Ok I just realized that I didn't replace all of the pulleys. Power steering or alternator. So I will have to check them.

 

[turbozig]

Sounds like an idler pulley bearing.... Hopefully not an alternator or power steering bearing...

I agree, sounds like an idler or tensioner bearing. If you remove the serpentine belt, a relatively simple task, spin the idler pulleys, it will be obvious if one is bad. How many miles on the car?

 

[JJVG]

The car has 132000 k but I just replaced the idler pulleys in the spring.

 

[Rruuff Day]

Take the belt off and spin the alternator and power steering pulleys with your hand paying attention to any scratchy or rough feeling. Since you hear it at an idle, might help us if you could record and post the sound you are hearing.

 

[2KforeverC5]

The car has 132000 k but I just replaced the idler pulleys in the spring.

Have you ever replaced the power steering fluid?

 

[JJVG]

Hi guys & gals. I found the source of the noise. My HVAC fan just stopped working and coincidence the noise started. When I turn off my HVAC the noise goes away. So now its just a matter of finding out what exactly has gone wrong in behind my dash? Yuck.

 

[JJVG]

Now my alternator pulley is starting to chirp. Seems like I have my work cut out for me when I park it for the winter. Installing a heat shield, replacing the hvac blower. I think I might have to replace the actuators, my windshield wiper fluid does not have a strong spray, even with the newly installed pump. And I think I might try and tackle the air bags in the seat to see if I can repair them. Well I'll have 6 months to get it done.

 

[JJVG]

Have you ever replaced the power steering fluid?

Not yet that sounds like a good plan for the off season.

 

[HANNOR]

I have a somewhat similar situation at idle i hear nothing but when i accelerate, i hear a whine/whislte at around 2500rpm. I changed belts, pulleys no improvement. Spoke to a mechanic and he told me GM Alternators are known to have this high pitched whistle. Anyone else experienced this?