No, there's no reason to.
unless they have mold or smell really bad, i'd say low.. but possibly food poisoning.
Bad oil pressure switch - $10 Clogged intake screen - $?? Bad oil pump - $1000 Worn bearings in engine - $a lot
NO! as long as you use it for the right reason, and are very careful!
Black and blue smoke means your engine is burning oil. That is bad. You may have a blown head gasket. That is very bad. You may have worn piston rings. That is also bad. I have no idea why your engine is burning oil but the reason is bad.
Not sure if it's bad, but there's not much reason to.
Excessive oil use, excessive water use, major oil leak, excessive smoking, ask a certified mechanic
Instead of using oil you can use butter this works just as well as oil sometimes even better .One bad thing is butter can be worse for your health then oil .Also there are oil sustitutes made out there.
Yes. It clogs the filters. Badly.
Yes
No, it is not. Use exactly what the manufacture recommends. What good reason would you have for doing otherwise?
I've herd of it, but it sounds like a bad idea.