15W40. Suitable for turbo diesel and petrol engines. Approved by Mercedes-Benz and Volkswagen. Turbo motor oil prevents black sludge. Valvoline Turbo motor oil is uniquely engineered to meet the demands of both (turbo) diesel and petrol engines. This unique formulation helps resist oxidation and prevent sludge formations on turbocharger bearings.It also aids in prevention of varnish deposits which can cause ring sticking in turbocharged engines. Valvoline Turbo motor oil prevents black sludge.