HD (Heavy Duty) oils are used for vehicles with oil filtration from the end of the 1950s. Monograde oils are changed seasonally, with higher viscosity for summer and lower viscosity for winter operation. A low SAE class (e.g. SAE 10) indicates a more viscous winter oil, while a higher SAE class (e.g. SAE 50) is more viscous and more suitable for summer use. A more viscous oil (higher SAE class) can also reduce oil loss and oil consumption in older engines.
HD monograde oils still offer advantages in seasonal operation, as they are generally somewhat more viscosity-stable and resistant to ageing than multigrade oils.
Caution! Every rule has its exceptions. If you are not sure, we will be happy to help you with our individual oil advice via our form.
