Sequoia Intermittent Engine Knocking

About a year ago my Sequoia started up with a knocking sound, but the knocking went away after a few minutes. I ignored it because I thought the knocking was due to the fact that I was parked on a hill overnight and the oil just needed some time to circulate.

However, just recently, my Sequoia started up with the same knocking sound as last year, but this time I was parked on level ground, and it was only parked for about an hour or so. - And just like the first time, the knocking went away after a few minutes.

Here's a video of the knocking sound that occurred recently and sounds the same as the knocking from a year ago - 2010 Toyota Sequoia Knocking at Idle

Questions

1. What is the reason(s) for the intermittent knocking?
2. If the knocking is caused by a mechanical failure, shouldn't the knocking occur more than what I've experienced (only twice over a year)?
3. Can you identify the cause of the knocking from the video?

2010 Sequoia - 5.7L - 173k miles

 

Timing chain tensioner? Spun bearing?

 

Could be. Thanks for the tip.

If it's the tensioner, maybe it's just gunk'd up and gets stuck once in a while. I'm going to try flushing the engine with BG EPR 109. Crossing fingers.

 

I have the exact same noise in my 2008. Have you figured out this issue? Mine is very intermittent

 

No, I haven't figured out the cause of the knocking noise.

However, I performed an engine flush using 22oz of BG EPR 109. The knocking noise disappeared immediately after the flush and didn’t return for about a month, at which point it lasted less than a minute. After that, the noise didn’t come back until recently—9 months later.

I can’t say for certain that the engine flush is helping the issue, but it seems as though it is. I’m planning to do another flush with the same product and will see if it improves the situation again.

 

I appreciate the information and I will have to give this a try as well.