300SD (126.120) L5-3.0L DSL Turbo (617.951) (1982)
30 Recirculating pump
The temperature switch (2) (cold engine lock) prevents starting of system at a coolant temperature below 35°C in functions "c" and "d" and thereby
makes sure that no cold air is blown against passengers during the winter.
Layout of temperature switch (cold engine lock) on 8-cylinder models
2
Temperature switch
The recirculating pump (30) is located adjacent to monovalve (11) and serves to maintain a uniform coolant flow through heat exchanger (b) also at low
engine speeds (Fig.) During controlled operation, the pump is switched on by signal "footwell flaps". Electric activation is by way of control unit.
Diagram of coolant circuit
1
Surface heat exchanger (starting 11/81)
2
Thermovalve (starting 11/81)
11 Monovalve
30 Recirculating pump
b
Heat exchanger
c
Return flow
d
Forward flow