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THE ORIGINAL BRITISH MOTOR OIL SINCE 1899

5W-40 Oils

Our 5W-40 engine oils. Your handbook gives the grade and specification your engine needs.

What 5W-40 means

5W-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 5W-40 flows more easily from cold than a 10W-40, and is thinner when hot than a 5W-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.

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