does this car have adjustable valves on its engine?

What kind of oil did they put in 'it shouldn't make a difference?

I have had a similar problem. I had a cheaper quality filter made by lubrifiner and ended up with a rattling lifter or two. I am in the prosess to getting parts to change them. not nice, I was told by Mercedes to use good quality filter or this happens. There is no adjustment as they are hydrolic.