why
#1
#4
So no complaints then? It maybe burning a little oil, nothing to worry about IMO, what kind/grade of oil are you running? I would run synthetic as when I switched to synthetic I now burn no oil as opposed to the 1L between oil changes before (this was on my '88 5.0 with 230k).
#6
No, I wouldn't worry about it, it could also be a carbon build up which looks somewhat like oil, but either way, it won't hurt anything, intakes usually have some oil or carbon or both, it's perfectly normal.