This noise is driving me crazy

2006 V6 Taco. I am trying to diagnose this noise but coming up short. It does it while idling and while accelerating while driving around. So far here is what it is NOT (things I’ve replaced, noise continues)

Serpentine belt

Alternator

Power steering pump and pulley

AC compressor and pulley

Probably not a vacuum line

At this point the three idler pulleys and belt tensioner are next on my list, though they all seem to be ok when I took the belt off. Any ideas?

In the video I am lightly depressing the accelerator pedal and releasing while in park to recreate the noise.

 

Take the serpentine belt off the truck, start the truck and see if the noise is still there.
Obviously don’t run it too long, as the water pump will not be cooling the truck during this time.
But it won’t hurt if you do this on a cool engine.

 

Take off the supercharger

I would agree, possibly tensioner but what about the water pump/fan clutch?

 

Someone on here had a problem with a vvti cam part making noise like this, I'll see if I can find the thread.

Here's the thread, but it involves a 4cyl. Maybe the vvti parts are similar.
https://www.tacomaworld.com/threads/engine-whine.676057/

 

Good idea. I’ll give this a try and report back. Hoping it’s something external. The engine was swapped last year with one that had 95k on it, so fingers crossed.

 

You look under hood and try to rev engine? See if you can isolate the sound?

 

Update: took belt off, and unfortunately the sound continued. My guess is an overly tensioned timing chain and something to do with the cam shaft balance. I did however find that the lower idler pulley could use a replacement, I’ll save that for last since it’s nice and easy lol

I’ll do a bit more prodding tomorrow, but at the moment it seems like I’ll probably be doing a bit of a tear down. Bummer since the engine it had that wound up getting swapped out just needed a cam shaft adjustment too. The shop I took it to thought it’d be easier just to swap vs rebuild. Probably should have just taken it on myself instead

At least I have a winter project I guess?

 

Look at your air intake hose, make sure its not cracked/pulling air if its cracked

 

Go buy a stethoscope at your local auto parts store and put it on your engine in various places to see if you can find where it is the loudest.

I recently had a similar noise on my first gen that ended up being a kick down cable improperly tensioned. But 2nd gens don’t have those unfortunately.

stethescopes are the way to go when trying to pinpoint a noise, especially one that you can recreate without the vehicle moving.

If you’re alone, find something you can wedge in between the seat and the gas pedal (I like to use a pry bar or a hood prop) to raise the rpm’s a bit and then go searching for the noise with the stethoscope.

I thought my transmission was screwed before finding it was the kickdown cable with the stethoscope, so try not to jump to conclusions. It could end up being something simple.

something as simple as a clogged pcv valve can probably make this noise.

 

Thanks all. I’ll hopefully have some help tomorrow and will pick up a stethoscope to go fishing while they rev the engine. I’ll check the air intake, MAF, and all the vac lines and connections along with the engine block and torque converter areas.