Hi, new member here. Bought my 08 Civic Hybrid recently, and noticed it has developed some rattling or knocking at low RPM (or at higher RPM, engine noise may have overwhelm it). I also noticed the sound doesn't come on immediately when I start it from cold, maybe running for around 1-2 minutes. It sounds like the noise engines make when it's VERY low on oil, but this is not the case. I also checked if the EGR is blocked, that is also not the case.

I am trying to determine if I should open up the valve cover for further inspection, or if the noise is somewhere else. Does your civic hybrid make a similar sound?

Idle to around 3k rpm:

Idle (more apparent at 15 sec of this video):

Any recommendation would be appreciated! Thank you!