Terex O&K Hydraulic excavators

Coolant capacity & service interval

Terex O&K hydraulic excavators require coolant with a capacity range of 85 to 150 liters. Service intervals include checking every 10 hours and changing every 72 months or 12000 hours. The data covers 4 configurations.

The configuration chart below lists fill volumes and service intervals for each engine and trim variant.

TypeSpecifications
RH 120E, Caterpillar C27 (2x)
  • Use: Extended
  • Capacity 150 liter (each engine)
  • Check 10 hours
  • Change 72 months/ 12000 hours
RH 120E, Cummins KTTA19C
  • Use: Normal
  • Capacity 150 liter
RH 120E, Cummins QSK19 (2x)
  • Use: Extended
  • Capacity 150 liter (each engine)
  • Check 10 hours
  • Change 72 months/ 12000 hours
RH 90C, DHT Caterpillar C18 (x2)
  • Use: Extended
  • Capacity 85 liter (each engine)
  • Check 10 hours
  • Change 72 months/ 12000 hours

Additional Notes

  • The Terex O&K RH 120E carries a 150-liter cooling system capacity per engine across all listed engine configurations, including the Caterpillar C27 dual-engine setup, the Cummins KTTA19C single-engine setup, and the Cummins QSK19 dual-engine setup. On dual-engine machines, total coolant volume is therefore 300 liters across both units combined.
  • The RH 90C DHT with dual Caterpillar C18 engines holds 85 liters per engine in the cooling system, a notably lower per-engine capacity than the RH 120E configurations. As with the RH 120E dual-engine rows, the total system volume doubles when both engines are counted together.
  • The extended use condition on the RH 120E Caterpillar C27 and Cummins QSK19 configurations, as well as the RH 90C DHT Caterpillar C18 configuration, ties to a change interval of 72 months or 12,000 hours, whichever comes first. Extended coolant life formulations are engineered to maintain corrosion inhibitor effectiveness over longer service periods than conventional coolants, which is what justifies the longer drain interval.
  • All three extended-use configurations share a 10-hour check interval for the cooling system. A 10-hour interval corresponds to a daily inspection frequency in typical heavy equipment operation, reflecting the importance of monitoring coolant level and condition in high-load excavator applications.
  • The RH 120E Cummins KTTA19C row carries a normal use condition rather than extended, and no check or change interval is listed for that configuration. Only the 150-liter capacity figure appears in the specifications for that row.