Cooling Radiator; Coolant Expansion Tank - BMW N62 Series Service Training

New Generation N62 Engine
All the components (with the exception of the transmission oil
radiator) can be removed for repairs without disassembling any
other coolant circuit.
All cable connections have been fitted with the quick-release
couplings which have been used in the past.

- Cooling radiator

The radiator is made from aluminium and is divided into a high-
temperature section and a low-temperature section by a
partition wall. The two sections are connected in series.
The coolant first flows into the high-temperature section, and
then back to the engine, cooled.
Some of the coolant flows through an opening in the radiator
partition wall to the high-temperature section, then on to the
low-temperature section where it is cooled further.
The coolant then flows from the low-temperature section (when
the ÖWT thermostat is open) into the oil/water heat exchanger.

- Coolant expansion tank

The coolant expansion tank has been removed from the cooling
module and installed in the engine compartment on the right-
hand wheel-housing.
Note
The expansion tank should never be filled to above the Max
marking during a service. Surplus coolant is expelled by the
pressure relief valve in the breather cap as it heats up.
It is also best to avoid overfilling the expansion tank after repairs
have been carried out on the cooling system since the newly-
designed cooling circuit ensures very good engine ventilation.
© BMW AG, Service Training
Course Contents/Background Material
Chapter 3 P.69