Tensioner Idler Pully Noise?

On Sunday I changed the serpentine belt on my 2010 V6 Auto Prerunner (113k). The install went fine and everything works as expected. Yesterday, I crank my truck with the A/C running, and when I put it into Rev or Drive I get this knocking from underneath.



If I turn the A/C off with the truck in Rev or Drive, the noise stops. However, If the truck is in park with the A/C on there is no noise either. I'm guessing the extra load of the AC and the truck in drive is causing the tensioner bearing to make this noise?

Thoughts?

 

Any thoughts on this one? I’ve read changing the tensioner assembly is a major pain.

 

Are you sure it's the tensioner pulley? Do you have an automotive stethoscope that you can use to listen to each pulley?

 

I do have a stethoscope. I’ll pull the skid plates and have a listen to each pulley. Odd that prior to the belt change there was no noise.

 

I can't tell the noise from the clip. Remove the belt from the tensioner and check each pulley for play by moving it sideways then spin it and feel for grinding.

Before that, try old trick below. I have a stethoscope also, but the sound to my sensitive ears is deafening. Most tensioner issues just need the bearing replaced, not the whole assembly. My thread on replacing the pulley bearings might be helpful.
https://www.tacomaworld.com/threads...arings-in-the-idler-tensioner-pulleys.480961/

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

 

Check to make sure the belt is in the grooves on crank and centered on all pullys. If all is good, turn AC off, start the truck. Get a flashlight, look at the front of the AC compressor. Is it turning?

That noise honestly sounds nothing like a bad pully.

What was the issue to make you change the belt?

When the truck is completely cold, maybe try removing the belt. Start the truck, listen for maybe 3 seconds in park, put your foot in the brake, put it in reverse for 3 seconds, the drive for 3 seconds. Turn the truck off. Any noise?

 

I checked the belt today and it was riding perfectly in all groves. I took a stethoscope and listened to all four pulleys. The #1 bottom idler pulley had a slight bit of noise, the #2 idlers were nearly silent, but the tensioner pulley was extremely noisy.

I’d like to replace the tensioner pulley with OE parts, but looks like you have to buy the whole assembly. I may buy the assembly and just swap the pulley.

Chuy, thanks for the links. Nice write up.