Conventional oil
You might still use conventional oil if your car was produced with conventional oil, and you prefer to stick with the factory fill oil. The majority of the volume in conventional motor oil is base oil, which prevents the engine from overheating and lubricates its moving parts to protect them from friction related wear. Chemical additives are included to inhibit rust and corrosion, prevent build-up of engine sludge, and improve oil flow at low temperatures.
Consider transitioning to synthetic for superior engine protection.