ENGINE | 642.896/992 in MODEL 906 |
View of engine from front left |
Y19/10 | Coolant pump switchover valve |
D20.10-1127-12
Location
The coolant pump switchover valve is located at the front on the engine above the belt pulley for the coolant pump.
Task
The coolant pump switchover valve controls the coolant feed to the coolant pump.
Body |
1 | Ventilation connection (atmosphere) |
2 | Vacuum pressure supply connection |
3 | Connection for the coolant pump vacuum unit |
Y19/10 | Coolant pump switchover valve |
S20.10-4525-01
In a de-energized condition the coolant pump switchover valve is open.
The coolant pump is cut-in in the post-start phase if one of the following conditions is met:
- the max. shutoff time (dependent on the model and engine power) of 500 s after engine start is reached
– the post start phases limits of the intake air and the coolant temperature and the injected quantity of fuel stored in the characteristics map of the CDI control unit (N3/30) (engine 642.8) or CDI control unit (N3/20) (engine 642.9) are reached.
– engine speed or injection quantity exceeds the defined limit value
- a "heating" request was received from the automatic air conditioning control and operating unit (S98)