Does anybody else with an OM606 engine notice that oil vapours tend to collect and pool around the injectors, most often at the back of the engine?

I'm quite certain its oil and not diesel as its yellow and smells like oil. Its not harming anything, but it does seem a little bit odd.

Also, I need to do an oil change. Whats the recommended oil these days, when last I did it (10,000 miles ago) I used 5W-40 fully synthetic.