The alternator failed on my 2013 Odyssey. When removed it was covered with oil, which caused the failure. The mechanic said that the head gasket was leaking. He question why they located it where they did since there was room. So occasionally have the health of your head gasket looked at.

 

It's probably not the head gasket but the valve cover gasket.

 

mine was the power steering pump leaking that caused mine to go bad.