Checking map-controlled engine cooling thermostat F265: Audi (ALZ, AWA)

Checking
map-controlled engine cooling thermostat
F265
Special tools and workshop equipment required
Hand-held multimeter
V.A.G 1526 B
Auxiliary measuring set
V.A.G 1594 C
CLIC hose clip pliers
V.A.G 1723
Test condition
Engine cold
Testing internal resistance of heating element
Pull off engine cover panel
arrows
.
Unbolt coolant expansion tank
arrow
.
Unplug electrical connector for
coolant shortage indicator switch
F66
at expansion tank (bottom) and move expansion tank to one side (coolant hoses
1 ... 3
remain attached).
Unplug electrical connectors at
intake manifold pressure sender
G71
item 1
and
intake manifold flap air flow control valve
N156
item 2
from front of intake manifold.
Release hose clips at connections
arrows
using
CLIC hose clip pliers
V.A.G 1723
.
Remove bolts
2
and
3
and detach
throttle valve module
J338
from intake manifold.
Detach vacuum hose
5
at intake manifold.
Unscrew nuts
1
and
4
.
Detach intake manifold from flanges.
Note
Block off intake ports in cylinder head with clean cloths.
Unplug connector
5
at
map-controlled engine cooling thermostat
F265
.
Note
Disregard
items 1 ... 4
.
Connect multimeter to thermostat to measure resistance.
Specification: 14 ... 16 Ω at 25°C.
If specification is not obtained:
Renew thermostat
Chapter
.
Function test of thermostat
Remove map-controlled engine cooling thermostat
F265
Chapter
.
Check the thermostat when cold.
The large valve head
arrow
must seal off the connection flange all the way round.
If not:
Renew thermostat
Chapter
.
Connect the contacts of the thermostat with a battery using test leads from
V.A.G 1594 C
.
Using pliers, carefully place the thermostat vertically into a pot of boiling water up to the flange.
Note
The electric heating element now additionally heats the wax in the thermostat.
Do not expose the thermostat to air during this test, otherwise the expansion element can become damaged.
Check whether the minimum travel of
a
= 7 mm is attained after 10 minutes.
If minimum travel is attained:
Disconnect voltage supply from battery.
If the minimum travel is not attained:
Renew thermostat
Chapter
.
Assembling
Installation is carried out in the reverse order; note the following:
Note
Renew gaskets and seals.
Secure all hose connections with the correct type of hose clips (same as original equipment)
Parts catalogue.
Slip intake manifold onto connecting hoses.
Secure hose clips at connections using
CLIC hose clip pliers
V.A.G 1723
.
Interrogate and, if necessary, erase the fault memory for the engine control unit, as faults are stored when the connector is unplugged
Vehicle diagnosis, testing and information system VAS 5051
.
Tightening torques
Component
Nm
Intake manifold to bracket
20
Throttle valve module
J338
to intake manifold
10