All hydraulic oil brands that are specifically designed for use in your carrier are also acceptable for use in our hydraulic hammers. The use of other hydraulic fluids may be permissible after consulting with our service department. During the summer months, or in areas with high temperatures, it is recommended that oils with a viscosity of category H-LP 36 or higher be used. At temperatures lower than -20°C, the hydraulic hammer should not be put into operation. For further instructions about other specific climatic conditions, please consult directly with our service department. Always refer to your Owners Manual for additional instructions from the manufacturer. Please feel free to call RJ Hammers with your questions. We are available Toll Free 7 days a week 1-888-651-0817.