I had this very same issue. It started when I first used Liqui Moly (10W60). By the time I've got home, the noise was there. Switched back to Castrol (the OEM stuff) and everything got back to normal. I don't have the answer though. Liqui is superb, really good stuff, but my engine didn't like it.
I am now using Valvoline VR1 20W50 and all is good.