You should use nothing other than the recommended viscosity of oil.
Too thick will cause as much problem as too thin. Thick oil won't flow as fast when cold and may not protect the tighter tolerances on a modern engine as well as the recommended thinner oil.
Too thick will cause as much problem as too thin. Thick oil won't flow as fast when cold and may not protect the tighter tolerances on a modern engine as well as the recommended thinner oil.