Thanks for the feedback. Well actually, the needle lingers around the 1 mark, sometimes slightly below it.

Valve knocking: Honestly, I'm not even sure what valve knocking sounds like, I think I've heard the term used before but I can't say for sure that it's what I hear in my vehicle. To me it sounds like rattling. I've heard a similar sound in my previous vehicle (Honda civic) when it got close to 180,000 miles. When I added a few liters of oil in my 190E, the sound wasn't as loud.