Does anyone know with absolute certainty the nature of the timing chain tensioner on the TSX? Is it hydraulic, mechanical, or a fixed tensioner?

I ask because I recently changed my oil and used full synthetic for the first time. I've noticed now that at 4000 RPM and up, the engine has a pretty distinct high pitched "ziiiiing" sound as it winds up. It sounds exactly how a timing chain usually sings when it has a lot of tension on it. It's actually sort of a cool noise.

Since synthetic oil perhaps has slightly different viscosity qualities, I could attribute the new sound effects to greater timing chain tension if the tensioner is hydraulic. Otherwise I probably ought to spend a little time checking out the source of the sound.

 

Never having removed the timing chain or tensioner before, but looking at the service manual pages 6-16 to 6-19, it looks like it is mechanical. There appear to be a spring in the tensioner that pushes on the tension arm which applies tension to the back of the timing chain. Sorry for the simple explanation, but the service manual is mostly pictures and that is what I see.