82 s10. oil in air filter box?
 

Opened the fikter box to inspect and noticed a film of oil over the housing and filter. Any answers to why?

hmmm. has it been losing/burning motor oil? Is it motor oil?
thinking maybe it is blow-by. blow-by is caused by engine wear, cylinder walls, piston rings, etc.
When was the last time you did a cylinder compression test? i would recommend doing one