Possible Alternator Noise?

Hey guys.. my first time asking for diagnosis help since joining but recently my truck started making a noise very similar to what’s found in a a video on the first page of this thread: https://www.tacomaworld.com/threads/need-help-finding-whining-noise-front-of-engine.411972/

I guess it’s the alternator going bad but what’s weird is I’ve only heard it when I have the truck in park so far. A few threads discussing the alternator whine seemed to have said that the whine happens in park and drive. I’ve only ever heard it in park so far - so could it still be the alternator? It’s also not consistent.. just on occasion when in park.

FYI no rough idle and no performance issues.

Should I be worried?

 

Test it, check for noise. Figure out if it is going/gone bad BEFORE it fails completely.

 

yeah next time I hear it I’ll hop out and put my ear at it and see if it sounds like it’s coming from the alternator. I’m sure it probably is as the noise is identical.

my only thought is that I may have a little bit of time considering it only does it on occasion.. and someone in another thread said it happens with their alternator from time to time and it’s just working that’s all.

 

I had a similar issue last summer with a '15 4.0L Tacoma - noise, but only in PARK when a/c compressor kicked on. Mechanics stethoscope revealed a lot of noise coming from the alternator. Truck was still under warranty, dealer said it was not alternator and replaced a/c compressor. Noise did not go away. They eventually replaced the serpentine belt, serpentine belt tensioner and 2 pulleys on the drivers side.

I'm not saying that my situation lines up with yours, just that it's important of verify the failing component.

Here's a clever video on how to find a bad bearing/pulley

https://www.youtube.com/watch?v=fHtLH_m9gN4

 

Thank you!

I drove in to work this morning and when I put her in park I sat for a second and the whining didn’t start.

I’ll keep waiting to check.