SAE Grade 30 | ISO Viscosity Grade 100 Diester-based oil is useful under normal operating conditions for 4000 hours in rotary vanes, and 8000 hours in reciprocating crankcases. Please contact Ultrachem for scheduled change intervals on high pressure units. Energy reduction: SAE Grade 30 | ISO Viscosity Grade 100 Diester-based oils have extensive data showing energy reductions on compressor drive units averaging 6.7% on recips and 8.3% on rotary screws. The diester oils are compatible with most currently used compressor components including seals, paints and plastics. However, some materials are not recommended for use with diester oils.