Mxsmanic wrote:
I don't know. I'm not an engine mechanic. But it seems like every
engine I ever see is covered with oil or grease or something. I do
wonder where it all comes from (something must be leaking if it gets
all over the exterior), but mechanics don't seem to find it odd.

I don't know what engines you're looking at, but all the aircraft
engines of airplane owners I know are clean, and our mechanics
definitely take issue with any grime/grease/oil on the engine. Again,
how would you know if something's there that shouldn't be if it is
covered with grime?

Shirl