After being driven by 2 teenage boys... and probably flogged... I got my 195k mile 190D back.
Now I notice an engine tick when its warm.
Oil pressure is good, and from a listen it sound like a loose valve clearance, but these 601's have hydraulic adjusters.
I think its due for an oil change, but while I am under the hood I wanted some ideas on what to look for.

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2009 Mercedes ML320 Bluetec