Coolant Circuit, Function; Engine Cooling Circuit - Mercedes-Benz OM 471 Introduction Into Service Manual

GF20.00>W>0001H
ENGINE 471.9 in MODEL 963
Shown with code (M5Z) Euro VI engine
version
1 Oil/coolant module
1.1 Coolant thermostat
1.2 Coolant pump
2 Cylinder liner
3 Cylinder head
4 Coolant manifold
5 Injection nozzle for regeneration of
diesel particulate filter
(only with code (M5Z) Euro VI engine
version)
6 Exhaust gas recirculation cooler
8 Fuel cooler
9 Compressor
12 Fan
14 Coolant feed to AdBlue" heater
KA Coolant outlet to cooler
General
The engines in model series OM 471 have a closed cooling system
(pressurized system). This means that coolant in the cooling
system, which is circulated by the coolant pump (1.2), absorbs the
heat from the hot engine components and > once the engine has
reached its operating temperature > it dissipates this through a
cooler to the outside air.

Engine cooling circuit

The coolant pump (1.2) is belt driven. If the engine is running, and
if it has not yet reached its operating temperature, then the
coolant pump (1.2) circulates the coolant inside the engine. In
vehicles with code (M7T) Coolant pump, control of the speed of
the coolant pump (1.2) is permanently monitored by the engine
management (MCM) control unit (A4) with the aid of the coolant
pump rpm sensor (B640), and adapted as needed through
activation of the coolant pump solenoid valve (Y631).
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i Introduction of engine OM 471 and exhaust aftertreatment > 09/2011 >

Coolant circuit, function

KE Coolant inlet from cooler
– This printout will not be recorded by the update service. Status: 09 / 2011 –
Because the coolant thermostat (1.1) is closed when the engine is
cold, the coolant flows over the coolant bypass duct into the
oil/coolant module (1) and is routed there past the closed coolant
thermostat (1.1) through the coolant pump (1.2) to the oil>water
heat exchanger.
The oil>water heat exchanger cools the engine oil if its
temperature is more than 115 ∞C (opening temperature of oil
thermostat), so that a temperature of 120 ∞C is not exceeded. The
oil>water heat exchanger is fastened to the oil/coolant module
(1), and it protrudes into the crankcase.
The coolant is routed in this way into the crankcase and therefore
to the cylinder liners (2). At the same time a portion of the coolant
is routed to the fuel cooler (8) and the compressor (9), as well as
over separate feed lines to the exhaust gas recirculation cooler (6)
and the exhaust gas recirculation positioner (Y621).
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Functions
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