While multigrade engine oils always make sense in colder climates, several US states are so warm that your vehicle may be better with one of our monograde oils.
Why might you need a monograde motor oil? Generally when you live in a warm climate. Multigrades are designed to flow easily when cold, but become more viscous when they're warm.
But if you live somewhere with high ambient temperatures, your car or light truck needs a monograde motor oil that is liquid engineered to protect from the moment the engine starts, resist thermal breakdown and keep delivering protection in even the hottest operating conditions.
The benefits of Castrol® HD 30 AND HD 40: