Stuff like this only cements my decision to stay with 5000-mile oil change intervals. When he popped the valve cover - it looked like many valvetrains posted here. And usual responses are along the lines of "varnish is not a problem", "what's the obsession with clean engines?". But seems to me that varnish IS a problem. A problem that causes damage where it can't be seen easily by simply removing the valve covers. Bearings, chain components, etc. Yet many disregard the varnish (i did too for a short period) and preach blanket statements that todays engines and oils are made so much better, that 10k OCI is the normal and any engine can do extended OCIs on almost any oil made today. If some varnish was able to kill an almost unkillable VK56, then many here should rethink OCIs and oil of choice in their engines.
5000-mile rule should stay, especially with basic non-EURO oils. Engines I own and maintain will keep getting Euro rated oils, (A3/B4 or better) at strict 5k OCIs.
Random rant o'clock. I guess this is my "Old Man Yells at Cloud" moment.

5000-mile rule should stay, especially with basic non-EURO oils. Engines I own and maintain will keep getting Euro rated oils, (A3/B4 or better) at strict 5k OCIs.
Random rant o'clock. I guess this is my "Old Man Yells at Cloud" moment.
