I need help!!! Belt Noise? I don't know

Hi folks,

I need help pinpointing the noise that is coming from the front of the engine. It sounded like a belt noise. I changed out the 2 upper pulleys and a tensioner and it still making noise. I'm just wondering if it could be my alternator that is on its way out. The belt only has about 20K miles on it. Could it be that the belt I got is crappy to begin with? I don't want to go out and buy a remanufactured alternator only to find out that the noise is still there. I included a video to show you the noise that I am talking about. Click on the Youtube link below

https://youtube.com/shorts/4rfYalF1yGM

 

Wouldn't it have been easier and cheaper to start with the belt instead of what you did? I would get an oem belt from Toyota dealer before anything else. Some things are just better when oem. Basic stuff like oil filters, wiper blades, spark plugs, belts, all mechanical fluids.

 

I’ve had belts one year old make noise. Especially if you run gravel roads frequently

 

i would put a socket extension to the top of the alternator, and then touch your head just in front of your ear with the other side of the extension-- it will transmit the noise, and if it is the alternator, it will be very apparent.

also, check the back of the older idler pulley's you haven't replaced. my brz had an intermittent 'belt squeak' that i also thought was the belt. but it turned out to be the idler pulley inner shield rubbing on the mount. the fronts appeared fine, but the back showed a different story





i ended up adding a washer to space the idlers off the mounts to fix it, as the new idlers bound up slightly upon installation.

 

Sounds like a bearing in one of the idlers. I would loosen the belt and see if they wiggle and have play in them. that's all i have to say. What do i know!

 

Why does that ac pulley look like it’s not turning or is it just the video

 

I used a stethoscope on the alternator and no abnormal noise to speak of. I’ll take a peek on using a washer on the idler pulley to see any changes on the noise. I will go out and get a new belt to start with……… thank you for the suggestions

 

i really wouldn't bother with the belt. if it happens this fast, it's going to happen again. something else needs to be fixed.



you said you replaced the idler pulley's, but was it only the upper two(between power steering/water pump/alternator)? because then i'm suspicious of the tensioner, which is just an idler on a spring loaded arm, and the lower idler, next to the a/c compressor.

 

because the a/c is off

the outer ring spins, but the central section is the clutch pack and will remain stationary unless the a/c system is engaged.

it's possible that the a/c clutch bearings are going out, but it's not extremely common.

 

That I know. It just looked the outer ring wasn’t spinning to me. Just an illusion.