Blue Diamond is a fully formulated CI-4 Plus/SL universal motor oil. Due to its 5W40 viscosity grade, Blue Diamond meets and greatly exceeds all heavy-duty diesel engine requirements for multigrade engine oil. A 100% pure synthetic motor oil, Blue Diamond is vastly superior to partial synthetics. In addition, Blue Diamond is formulated to meet and exceed API SL for gasoline engines.
Blue Diamond’s 5W viscosity at low temperatures allows it to replace conventional 5W30, 10W30, and 15W40 oils in diesel as well as gasoline engines. This 5w property also helps oil get to the top of the heads faster on cold starts, while still maintaining the viscosity needed at normal operating temperatures. This is especially helpful on diesels with HEUI injection systems, pressurizing the oil rails faster than a 15w-40 would.