Loud rattle when parked or idling with the brakes depressed.

So I took this video maybe 10 days ago. The noise is only noticeable when stopped. I've heard it while in park or just at a red light. It doesn't always happen but when it does it's quite loud. 170k miles. Regular oil changes, not much else. Reliable vehicle. I believe in this video I was in park and applying and releasing the brake to the floor multiple times. It seemed like the rattle would occur more often with the brake applied and would disappear when releasing the brake, but it wasn't 100% that I could say the rattle only occurs with the brakes applied.

Can any of you Tacoma experts diagnose this issue on the sound alone?

https://youtube.com/shorts/qLT7z4VoDw8?feature=share

 

Maybe belt tensioner. Kinda sounds like what I have going on. If you have a long screw driver or ratchet extension be careful and stick it on the tensioner or pulley bolt and put your ear up to the other end and listen for the rattle.

 

I have a 1grfe 4Runner with 150k. Had a strange rattle when idling and only when turning the steering wheel. I initially thought PS pump but used the stethoscope and determined it was the tensioner pulley bearing. Connected a bunch of extensions to a bucket which acted like a speaker. Since depressing the brake uses vacum, this may be altering the rpm to induce pulley rattle...

With 150k I decided to replace all of them. The tensioner solved the issue.

FYI if it's the tensioner. Not a lot of options for replacing just the pulley or bearing. I ended up replacing the entire assembly with the Gates tensioner. Took about 2hr and requires the Alt and AC compressor to be disconnected and fan to be removed. Unfortunately the Gates pulley cannot be swapped on the Toyota tensioner since the offset is different but I'm glad I put in the new tensioner. If you go Gates also note that the tensioner pulley bolt is 13mm vs the OEM 14mm. In hindsight I wish I would have gone OEM since I found one via Toyota parts online for $20 more than the gates.

Good luck, keep us updated.