15W-40 Oils
Our 15W-40 engine oils. Your handbook gives the grade and specification your engine needs.
Diesel Gard 15W-40 CI-4/SL
A top-tier multigrade diesel engine oil for heavy-duty diesel engines.
Diesel Gard 15W-40 CK-4/SN
A top-tier multigrade diesel engine oil for heavy-duty diesel engines.
Diesel Gard 15W-40 LE
A high shear stable high-quality mineral engine oil designed for use in high output, high-speed diesel engines.
Fleetmaster 15W-40 CF-4
A multi-grade diesel engine oil for heavy-duty diesel engines.
Q 15W-40 SN Plus
A mineral-based engine lubricant formulated using updated additive technology and high-quality virgin base oils.
QT Plus 15W-40 SN/MA2
A mineral multi-grade engine oil, designed using current additive technology and high-quality virgin base oils to meet the requirements of modern four-stroke motorcycle engines.
What 15W-40 means
15W-40 is an SAE viscosity grade. The first number, followed by W for winter, shows how easily the oil flows when cold: the lower the number, the faster it reaches the engine at start-up. The second number shows how thick the oil stays at normal running temperature: the higher the number, the thicker the oil.
So a 15W-40 flows more easily from cold than a 20W-40, and is thinner when hot than a 15W-50.
Use a grade your car's manufacturer lists, with the specification it asks for as well: oils of the same grade can meet different specifications.
More in our guide to what the numbers on engine oil mean.