Diesel Engine Oils
Heavy-duty diesel engine oils for on-highway trucks and fleets, and for off-highway and agricultural equipment. Every grade is formulated to API CK-4 and supplied in 205 litre drums.
Endura Series Heavy-Duty Diesel
Three viscosity grades cover North American heavy-duty diesel service: a full synthetic SAE 5W-40 dual-rated CK-4 / SP for mixed fleets, and SAE 10W-30 and 15W-40 for engines specified on the conventional grades. Every grade is built to handle soot and hold its TBN over a long drain without upsetting the after-treatment.
Tell us the grade, specification and annual volume you need and we will confirm availability, lead time and pricing. Quotes are available in USD or CAD. Start a conversation.
What API CK-4 Means
CK-4 is the current API service category for heavy-duty diesel engine oil. It is the shorthand an engine manufacturer's manual uses, so it is worth knowing what it certifies.
API CK-4 was introduced in December 2016 and replaced CJ-4. It raised the bar on oxidation stability, shear stability and aeration control, the three properties most stressed by higher-output, higher-temperature engines running long drain intervals. It is backward compatible: where a manual calls for CJ-4, CI-4 PLUS, CI-4 or CH-4, a CK-4 oil of the correct viscosity grade meets it.
CK-4 has a companion category, FA-4, which uses a lower high-temperature high-shear viscosity to gain fuel economy in engines designed for it. FA-4 is not backward compatible and belongs only where the manufacturer explicitly allows it. Every SIMCOE diesel grade is CK-4, not FA-4, so it can go into any engine whose manual calls for CK-4 or an earlier category.
API CK-4 is a performance standard, not a manufacturer approval. SIMCOE formulates to meet it and does not hold licensed OEM approval marks. Where a manual names a specific manufacturer specification alongside the API category, follow the manual.
Drums, Part Numbers and Documentation
Diesel grades ship in 205 litre drums, which is 54.2 US gallons. Pails, kegs and 5 litre jugs are quoted on request. Part numbers for drum formats are confirmed on quotation.
A certificate of analysis is issued per production batch, giving measured kinematic viscosity at 40°C and 100°C, viscosity index, HTHS, flash point, pour point and total base number for the batch you actually received. Request the current batch report from the lab reports library.