Coolant circuit as-built condition

P20.00-0405-06

1 Compensation tank

2 Overflow line

3 From the cylinder head to the radiator

4 Return from heater (heat exchanger)

5 Fuel heat exchanger

6 Feed to heater (heat exchanger)

7 Heater heat exchanger

8 Coolant thermostat

9 From the radiator to the coolant pump via the coolant thermostat

10 Overflow tank (engine 603.96)

11 Radiator

12 Filling hose

13 Vent pipe

A Heater

C Cooled water

D Radiator circuit in excess of 100 °C

The 602-603 engines are equipped with a sealed cooling system. The coolant circuit is regulated via the coolant thermostat (8).

A distinction is made between short-circuit operation (up to approx. 85 °C), mixture (85 - 100 °C) and operating state (in excess of 100 °C).

The duo valves are used to control the coolant temperature in the heater's heat exchanger (7).

In the compensation tank (1), the temperature-dependent volumes of the cooling system are compensated.

An overflow tank is installed in the 603.96 engines.

The overflow tank protects the engine against coolant loss in the event of high ambient temperatures.
In the event of high ambient temperatures, coolant may escape at the overflow line after the engine has been switched off. The overflow tank collects this escaping coolant.

After the engine and the coolant have cooled off, this creates a vacuum in the cooling system, which forces the overflowed coolant back into the compensation tank from the overflow tank.