If your car needs a 10W-40 engine oil Castrol offers a range of options that flow like a 10 Weight oil when the engine is cold and a 40 Weight oil when up to normal operating temperature.
Castrol offers a broad range of 10W-40 engine oils, including premium full synthetic, high mileage and conventional, meeting the needs of both drivers and vehicle manufacturers.
There are two things you need to know to find the right oil for your vehicle 1) the viscosity, 2) the manufacture specification requirements. The products on this page are all 10W-40 viscosity and also show the manufacturer specifications details.
To find the product you need always consult your vehicle handbook.