However, I can't figure it out.
I took a video.
I replaced timing chain tensioner and it is not the leak point.
In this case, timing chain cover makes oil leak??
You can see below
Is that a timing chain cover right?This oil leak looks minor.
Unless you degrease the engine then check carefully, it's hard to find the leaky spots.
The timing chain cover is likely to leak.
Also the interface between the 3 surfaces, timing cover, cam shaft cover and cam head will have small leaks unless RTV is applied to the gasket at those 2 spots. It's an easy fix. Remove the cam shaft cover and apply RTV on top and bottom of the gasket at those 2 spots. See if it stops the leak.