ROTELLA 550019903-12PK T1 30 Heavy Duty Engine Diesel Oil (CF/CF-2) - 1 Quart Pack of 12 Have excellent wear protection that promotes engine durability Low ash content minimizes formation of deposits and keeps intake ports clean Outstanding oxidation resistance that maximizes service life Excellent rust and corrosion protection of critical engine parts High dispersancy-detergency protects against sludge and varnish deposits Rotella Heavy Duty, engine oil features multi-functional, low ash additive technology in a synthetic base oil designed to provide highly responsive protection that continuously adapts to your driving conditions.