Repair Service Manual

REPAIR MANUAL
1
KUBOTA Z402 and Z602 engines
Cooling system
Forced circulation cooling system with water pump. Temperature regulation is ensured by a
thermostat fastened on the upper water manifold of the cylinder head.
The thermostat is controlled as defined below:
Start of thermostat valve opening
69.5 to 72.5 °C
Full opening of the thermostat valve
85 °C
The water pump is centrifugal and driven by the accessory belt.
1 : Radiator
2 : Water pump
3 : Fan
4 : Thermostat
5 : Cylinder head
6 : Engine block
Quantity of coolant: 2 litres
A: Thermostat closed, short circulation enhancing
engine temperature build-up
B: Thermostat open, long circulation to cool the engine.