What is this noise? Can anyone identify?

I've got a coworker with a 2009 Toyota Tacoma Off-Road with 95k miles that is getting a weird noise from the engine that comes and goes. It sounds like rod knock a little but it goes away so he thought it could be something else. Anyone have any idea what it could be? Sorry for the poor quality of video, you may need to turn up the volume to hear it.

https://www.youtube.com/watch?v=UZK8Liih5QA

 

Sorry to hear about your troubles. Can you tell us if this noise appears with the engine running only or are you driving?

 

He gets the issue when it is running and driving only on occasion. Again, it isn't constant nor does it show up each time he drives.

 

Seems to low a frequency to be a rod. I'm betting a bearing on an accessory.

 

I would check the wheel bearing is not leaking....see if there is any weeping (sign) around the rear axle and or check the oil level of your rear differential. If you have the time and floor jacks you can raise the rear axle and check for movement on the axle....
Symptoms Of A Worn Hub Bearing:

• #1 – Clicking, snapping or popping. ...
• #2 – Grinding while in motion. ...
• #3 – Clunking or knocking. ...
• #5 – Wobble and/or wheel vibrations. ...
• #6 – Shimmy, shudder, or vibration at constant speeds

Keep us posted...good luck.

 

Rod knocking like that would most likely have already made its exit via the side of the block

If he revs the engine a little (neutral, no load) a rod knock usually will make itself known as the engine is returning to idle... from the audio I’m hearing something in the trans/torque converter area?

 

I should have mentioned in the first post, this video is taken when the truck is in park and not moving. My experience with hub bearings would be the vehicle needs to be moving and it doesn't go away.

 

My 2009 makes a similar noise during cold start in cold weather, 160K on the truck, new idler bearings, and water pump. The noise goes away after warm-up.

 

We hear this complaint around the same time every year. Only when it gets cold outside. My 2009 Sport had the same symptoms. Sounds like the noise is coming from down by pedals.

Believe it or not...its the intake snorkel vibrating on the fender. The foam gasket on the snorkel fails.

Don’t believe me...take off the end of snorkel mounted to fender and see if noise goes away.

This was my video on youtube:
https://m.youtube.com/watch?v=Xf6eA5kxe2k

 

Thank you! We'll check that out and see if that's it.

 

So it doesn’t seem to be the intake snorkel. He got another video that you can hear it much better:

https://m.youtube.com/watch?v=lvGjFuUpZLc

 

So I've had my CAI removed for last month and half or so. Have had no noise since. Had plenty of cold morning starts. Even had one the other day at 0 degrees, no noise. Put CAI back on the other morning and at 30 degrees the noise is back and have heard it almost every cold start since. For the life of me I cant wrap my head around what is causing the noise.

Plenty of foam insulation on intake where it rest against the fender. Even put rubber washers under the mounts bolted to fender apron.

Cant understand why the noise is heard by the brake and accelerator, and why such a strange noise? See my video at post 9. Just really strange. Sound is exactly like video in OP’s post. Have had it off and on now for last ten years. Always a cold start but not all the time.

Have started in my garage at 50 degrees no noise, back out into driveway on a cold morning and it immediately begins rattling. Matter fact when I recorded the video it made no rattle when started in garage, only to begin making noise when I backed out into driveway.

Definitely not something detrimental to the operation of motor and components. Truck runs like new. Just bothersome to say the least. Wish there was an answer.

 

I'm having this same issue. Did you and your friend ever find the culprit?

I'm going to try looking at my intake at the filter, though I don't have a CAI installed. I'll be grateful for any insight.

Thanks!