2014 GLK350 with m276 engine - time to get into timing parts

[engatwork]

I recently changed out the timing chain tensioners thinking that was going to quieten down the rattle I hear on cold start at 250k miles. Now after doing a little more research it sounds like it is probably one of the camshaft adjusters. Fault code is intake cam bank 2 so that is where I'll start. I'm also seeing where the timing plate on the cam can slip. I do not hear it on every start, just every now and then. Any thoughts/comments regarding this job please let me know.

Is the chain loosest (on both banks) at 40d past top dead center? That is the way I understood it when I read through the procedure.