You asked if there should be concern. For this engine yes. Molakule is right, but its also true that heat/flashing/volatility can cause varnish. The latter is the case on this engine. I fixed one, assisted with a few others. Its always the same 3 bolts. At the intake manifold. Where the aluminum block is at its thinnest. (piston on one side, coolant channel on the other). What makes aluminum threads strip? Heat. It gets soft. Under torque the bolts can pop loose. Will it happen? Maybe, maybe not. If you look at the block design, clearly the coolant is playing a role keeping that section of the engine cool. So I suggested keeping on top of your coolant, because I think thats what causes/exposes the problem.
Concern means keep an eye on engine temps, does not mean the sky is about to fall. was just answering your question. Nothing unusual about the pics for your engine. Here's another one, same thing. Hot oil vapors rising on the cover just like yours.
Concern means keep an eye on engine temps, does not mean the sky is about to fall. was just answering your question. Nothing unusual about the pics for your engine. Here's another one, same thing. Hot oil vapors rising on the cover just like yours.