Oil in the reservoir. No evidence of external leaking, but I will double check that before I get into,this.

Last time I used new bolts. Checked for flatness with feeler gauge and 12” steel ruler, not ideal I know. No history of overheating. What brand of head gasket do people like? Copper spray or not? Im pretty disappointed in this but in 10 years this is the only hiccup.

I’ve had three of this model, and done two head gaskets. It might be a feature. Not hard to do, just tedious.