Coolant circuit and engine cooling - RA20001200050X(20-0050)
Engine off cooling
If the coolant temperature is < 100 °C after switching off the engine, the coolant temperature is monitored for a period of 1.5 minutes. If the coolant temperature rises above 110 °C during this time as a result of being heated by the engine, the heating water circulation pump of the coolant circuit is operated in order to avoid any local overheating and the formation of vapor bubbles.
The maximum duration of the engine off cooling is 10 minutes. The engine off cooling program is ended prematurely if the coolant temperature is < 110 °C.
Position of the components when engine off cooling operating.
- Power supply relay (K30) "On"
- Heating water circulation pump (A31m1) "On"
- Heater blower (A32m1) "Off"
- Pulsed valve (A31y1/2) closed, bypass circuit for engine off cooling open
| Engine | Thermostat start of opening | Fully open |
|---|---|---|
| 120 | 87 °C | 102 °C |
Coolant thermostat
The coolant thermostat (4) is installed in the cover (3) and prevented from turning, which produces a defined position of the vent valve (5). The coolant thermostat housing (1) is fitted together to the left coolant outlet connection (6) and to the right connection (7) and sealed on each side by a O-ring (8).