Aral Turboral 20W-50

Worth knowing

The only code in this oil’s record, API CH-4, is a class, not an engine manufacturer’s approval. An approval is built on a class and adds requirements of its own: Cummins CES 20076, for example, requires CH-4 plus a 300-hour test on a Cummins M11 engine, so the class alone is not enough for it. According to the description of the class, the service life of CH-4 oils is less sensitive to fuel with a sulphur content above 0.5 %, and Aral too mentions engines running on fuel of varying quality. The base number, that is, the reserve of additives that neutralise the acids from sulphur, is 7.9 mg KOH/g here, lower than that of Turboral 15W-40 (10.6) and Turboral 10W-40 (10.5). The article on the API CH-4 class explains what the class requires and which older classes it replaces.

The rest of the Turboral line, apart from the 20W-20 with no class at all, has newer classes and manufacturer approvals, but comes in 5W-30, 10W-40 or 15W-40. Other oils of this class, of various brands and viscosities, are collected on the API CH-4 page.