BMW 5251 Service Manual page 307

Camshaft Timing chain1
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Remove Automatic Stability Control (ASC) throttle body:
Disconnect electrical harness from throttle position sensor.
Disconnect ASC actuator cable (arrow).
Remove 3 mounting fasteners and remove throttle body.
4
Disconnect fuel tank vent valve line and cap off line (arrow).
-
Drain engine coolant and remove hoses from thermostat
housing. See 170 Radiator and Cooling System.
-
Remove water pump and thermostat housing. See 170 Ra-
diator and Cooling System.
-
Remove left side upper timing chain cover retaining bolts and
remove cover.
4
Counter hold right intake camshaft
CAUTION-
Counter hold camshaft with a 27mm open-end wrench while
loosening sprocket bolts. Grind wrench if necessary to pre-
vent damage to head.