Any clue what this cold start noise is?

I found the exact noise on youtube. Noise sounds like wah wah wah wah wah. If that makes sense haha. It goes away once the truck starts to warm up. Seems like plenty of people in the comments have the same noise with no negative affect. I'm just generally curious what it is.


https://youtu.be/mUyZPzv9seg

 

open the hood, get a mechanics stethoscope and listen. Hell you can even use a wooden dowel etc.

A good first thing to do is simply pull the belt off the motor so no accessories spin. Start the truck up (dont run long, water pump is spun off the belt), if noise is gone its something that the belt spins. If noise is present its inside the motor.

 

I was considering doing this but figured I would check first. People in the comments were claiming this noise on brand new 4.0 tacomas.

 

I recorded the sound of my 2015 4.0L when it was 9 months old. The sound is similar to what the OP posted, but not as loud. What I hear and what my iPhone heard are 2 different things. I heard a quieter engine than my phone.
It's my belief these uploaded recordings are not always easy to evaluate.

 

This. My taco makes all sorts of clacking when cold. But ya know what, it doesnt use an ounce of oil, has great compression, gets decent mpg, and always starts.