Audi V8 Service page 18

Engine - Mechanics
Previous design:
The coolant thermostat is connected to the
"small coolant circuit" via two holes in the
cylinder crankcase (see Fig. 217_017).
The holes are directly connected to the
cylinder-head water jacket (1st cylinder) and
the water jacket of the cylinder crankcase. The
heated coolant flows from the 1st cylinder to
the coolant thermostat.
New design - modified components:
– Cylinder head in bank 1 modified
– Additional coolant pipe
– Rear coolant pipe modified
The connection in the cylinder head to the
water jacket (cylinder crankcase) has been
split (see Fig. 217_019).
The coolant from the rear coolant pipe is
forked by the new coolant pipe (mixture from
all cylinders) and then passes through the
cylinder head to the two holes which lead off
to the coolant thermostat.
This ensures uniform temperature control.
The function of the cylinder head is to
connect the coolant pipe to the two holes
leading off to the coolant thermostat.
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New coolant pipe
From radiator
Coolant thermostat
To coolant pump
New design
Coolant pipe
(return for heater, oil cooler
and expansion tank)
SSP217_018
SSP217_019
SSP217_017