Hi, All!

How do you know when to use an engine oil that has a higher or lower viscosity in a car or truck?

For instance: Does it have to do with the season of the year? Perhaps the size of the engine? The age of the engine? The location where the vehicle is being driven?

Maybe even other factors?

Thanks!

Typically it's the temperature range expected. A lawn mower is expected to operate in the summer thus it has a higher viscosity than snowblower oil.

One might use a higher viscosity oil when the rings are worn.

As the link below states the oils used in a car are multigrade and the W stands for winter. The engine has a lower viscosity at low temperatures and then has a higher viscosity as the engine warms up. Your owner's manual for your car has a temperature range and the oil viscosity to use.

BMCNO Motor Oil 101