Castrol® Assuron™ are high performance, straight grade, heavy–duty engine oils that couple selected base stocks with a carefully balanced additive package. Castrol Assuron by design will enhance engine performance and protect engine parts for extended life and reduced maintenance costs. Castrol Assuron has proven performance in various on– and off–highway heavy–duty diesel engines, particularly in applications requiring API CF–2. Castrol Assuron lubricants are extremely resistant to the formation of high temperature deposits. The higher dispersant package also works to help keep harmful deposits from the cooler areas of the engine. Castrol Assuron exceeds the requirements of the following API categories: SAE 10W (CF), 30 (CF–2, CF), 40 (CF–2, CF), 50 (CF–2, CF). Castrol Assuron meets the requirements of General Motors Corp. (Allison Trans. Div.) C–4.