1996 Other Saturn Models oil in antifreeze back up bottle

Hi there, are you sure it's engine oil? If it is most probable cause is a head problem, and it can be fixed, but tour mechanic will have to dismantle first to astatine extent of damage. As it is an auto, check if trans cooler is internal of radiator, (two pipes going into the side or bottom of radiator) often the inter cooler pipe fractures and trans oil enters the cooling system, worth checking before removing head.

Mark (mhpautos)