10W-40 Engine Oil
Our 10W-40 engine oils. Not sure 10W-40 is right for your car? Find My Oil will tell you from your registration.
Classic Q 10W-40
A semi-synthetic multigrade for modern-classic petrol and light diesel engines, with excellent high-temperature stability and smooth cold starts.
QS 10W-40 RMV
Advanced semi-synthetic modern passenger car engine oil protecting multivalve sumps.
What 10W-40 means
10W-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 10W-40 flows more easily from cold than a 15W-40, and is thinner when hot than a 10W-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.
Not sure which grade your car needs? Check what oil your car needs by reg.