Hi, everyone,
In the past one month or so, I have noticed some belt noise from front passenger seat when the car is on. It's there all the time, but more noticeable when the engine is idling, like stopped at a traffic light.

I have tried pinpointing it by popping up the hood while the engine is idling, but I couldn't hear it out of the car with the operation sound of engine.

I also tried recording it with my cell phone, but my phone can NOT catch the noise. I guess some belt is wearing out prematurely.

by the way, I just checked the Owner's Manual, our car has Timing Chain, not Timing Belt.

Does anyone have this experience?
Alex

 

Since you cannot capture the sound or reproduce the sound you may consider taking it in to a shop to have it checked out. Although if you cant reproduce the sound they may not be able to do much either.

 

Are you certain it is from the belt itself? Have you inspected your belt? Have you checked that it is tight enough/not overtightened? Have you tried using belt dressing to see if that makes it go away?

 

Although the noise can't be captured by the phone, but people can hear it. I'm sure the tech will be able to hear it when I take my car in. I just wanna ask my G37 folks if this has happened to them before I make a trip to the dealership.

Yes, I believe the noise is from the belt. I'll check the belts myself a little bit.

I'll come back to report the root cause to you guys.

 

Is it a squeak or squealing noise or something else?

 

Belts really only make two noises:
1) when slipping they make a horrible squeaking noise
2) when they are close to failure and sections of the inside grooves have worn/flaked away they slap and it sounds like an engine knock. This sound is actually the outer band of the belt slapping against the pulley or tensioner surface. IN this case you can visually inspect the inside of the belt and you would see it.


If you're hearing something else it could be just about anything.

If you really want to pinpoint the noise buy a mechanics stethoscope and the source of the noise will be obvious. If you're a shadetree mechanic (like me) you can use a really big screw driver. Place the tip of your screwdriver on various parts and place the handle end firmly against your year. You would be surprised at how well this works. I've diagnosed bad bearings, bad fuel injectors, and yes.... a fractured belt with this method. Just be careful any time you stick anything (especially your head) near a running motor.

brian

 

Thanks Brian! your input is very helpful.
I think it's noise (2).

Sometime ago, i bought a long screwdriver to change the cabin filter. It looks like there is another way to use it. Thanks for your tips!
Alex

 

Although if you cant reproduce the sound they may not be able to do much either.

 

got my car back!

The technician found out the fuel damper was broken.

They ordered a new part, installed it and the noise is gone now.

Hope this info is helpful for you guys. Again, the noise came from passenger side dash area, sounded like a small toy motor.

I'm happy my car is good now!