What I think is oil is shooting up into the air filter on topBlown head gasket
Stuck crank case vent
Overfilled sump
How is oil getting into the muffler and air filter housing with no oil in the engine? "but I haven’t filled it with oil" ????My 18hp vanguard is leaking oil into the muffler and the air filter area but I haven’t filled it with oil and it wasn’t doing this earlier today