1997 BMW 528i Coolant hose

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Radiator and Cooling System
Cooling system, bleeding
Trapped air in the cooling system can prevent proper coolant
circulation and overheating. Wheneverthe coolant is drained
and filled, bleed the cooling system to remove trapped air.
4 Loosen bleed screw (arrow) on radiator expansion tank.
- Set temperature controls in passenger compartment to full
warm, set blower to low setting and turn ignition to
ON posi-
tion (do not start engine).
CAUTIOIG
On late model cars with latent heat pump, do not turn ignition
to ON position.
- Slowly add coolanUdistilled water mixture to expansion tank
until it spills from bleed screw. When coolant spilling from
bleed screws is free of air bubbles, tighten screw and replace
cap on expansion tank.
Run engine until it reaches operating temperature,
- After engine has cooled, recheck coolant level.
Top up so that coolant level indicator is at MAX.
- If trapped air cannot be bled manually, pressure-bleed sys-
tem using cooling system pressure tester.
CA UTlON--
Always use genuine BMW coolant or its equivalent to avoid
the formation of harmful, clogging deposits
in the cooling sys-
tem.
Tightening torque
Radiator bleed screw to radiator 2.5 Nm (22 in-lb)
Mechanical (viscous clutch) cooling fan,
removing and installing
The procedure given here describes the removal of the me-
chanical fan and fan shroud. It is possible to remove the fan
without the shroud.
< Working at top of fan shroud:
Remove expansion tank bleed screw (arrow) and expan-
sion tank locking tabs.
Push top of expansion
tank toward engine and lift to free
from lower mounts.
- Remove two expansion rivets in upper corners of fan shroud.
Unclip expansion tank bleed hose located under shroud.

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170-1 6
I Radiator and Cooling System
- Remove fan and fan shroud mounting fasteners. Slide fan
and fan shroud downward to remove.
- Reinstallation is reverse of removal.
Thermostat, removing and installing
(M52 engine)
The coolant thermostat is installed in a housing at the front of
the engine.
- Drain coolant from radiator and engine block. See Coolant,
draining and filling (6-cylinder models).
WARNING -
Allow the cooling system to cool before opening or draining
the system.
- Remove mechanical cooling fan and fan shroud. See Me-
chanical (viscous clutch) cooling fan, removing and in-
stalling.
- Disconnect coolant hoses from thermostat housing.
- Remove thermostat housing from front of engine.
- Remove thermostat. Note thermostat direction and orienta-
tion before removing.
- Installation is reverse of removal, noting the following:
- Use new O-ring and gasket(s) when installing thermostat
and housing.
NOTE-
Some thermostats have a direction arrow or vent hole near
the edge. Install the thermostat so that either the arrow or
hole are at the top.
Fill system with coolant as described in Coolant, draining
and filling (6-cylinder models).
CAUTION-
Be sure to reconnect ground wire@) at thermostat housing
mounting bolt, where applicable.

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Radiator and Cooling systeml
Tightening torques
Block drain plug to block 25 Nm
(18
it-lb)
Coolant hose clamp (32 - 48 2.
5 Nm (22 in-lb)
mm hose diameter)
Radiator drain plug to radiator
2-3Nm(l8-27in-lb)
Thermostat housing to cylinder
head 10 Nm (89 in-lb)
I Coolant thermostat housing assmbly- - I
Thermostat, removing and installing
(M52 TU or M54 engine)
4 The electric map-controlled thermostat is part of the thermo-
stat housing at the front of the cylinder head.
1. Bolts (M6)
2 Bolt (ME)
3. Housing with thermostat
4. Gasket
- If a faulty thermostat is suspected, use appropriate scan tool
to interrogate
ECM for stored fault codes.
- Drain radiator and engine block. See Coolant, draining and
filling (6-cylinder models).
CAUTION-
Allow cooling system to cool before opening or draining the
system.
- Remove cooling fan and fan shroud. See Mechanical (vis-
cous clutch) cooling fan, removing and installing.
- Disconnect electrical harness connector from thermostat
housina.
4 Lever out retaining clips (arrows) and pull hose fittings off
thermostat housing.
- Unbolt and remove thermostat housing from front of engine.
Loosen nut at top of engine lifting eye to facilitate removal.
- Installation is reverse of removal, noting the following:
Keep sealing faces free of oil.
* Use new sealing gasket.
When reinstalling hose to thermostat housing, install clip
on hose end fitting, then push hose onto housing until it
clicks into place.
Fill system with coolant. See Coolant, draining and fill-
ing (6-cylinder models).

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Tightening torques Block drain plug to block
25 Nm (18 ft-lb)
Radiator drain plug to radiator 2 - 3 Nm (18 - 27 in-lb)
Thermostat housing to
cylinder head 10 Nm (89 in-lb)
Thermostat, removing and installing
(V-8 models)
The electrically-heated thermostat is an integral parl of the
thermostat housing. The operation of the thermostat is moni-
tored by the engine control module (ECM).
- If a faulty thermostat is suspected, use appropriate scan tool
to interrogate ECM for stored fault codes.
- Drain radiator and engine block. See Coolant, draining and
filling
(V-8 models).
WARNING -
Allow cooling system to cool before opening or draining the
system.
- Disconnect mass air flow (MAF) sensor electrical harness
connector. Remove air intake duct together with MAF sensor.
- Remove mechanical cooltng fan and fan shroud. See Me-
chanical (viscous clutch) cooling fan, removing and
in-
stalling.
Disconnect electrical harness connector (arrow) from ther-
mostat housing.
Remove coolant hose from thermostat housing.
NOTE-
M62 engine: Hose is clamped on.
M62 TU engine: Hose is attached with quick-disconnect fit.
ting. Remove clip to disconnect hose.

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170-1 9
Radiator and Cooling System
Coolant pump Remove thermostat housing fasteners
(arrows) and remove
thermostat housing.
Installation is reverse of removal, noting the following:
- Keep sealing faces clean and free of oil.
Use new sealing gasket.
Fill system with coolant. See Coolant, draining and fill-
ing
(V-8 models).
Tightening torques
Block drain plug to block 25 Nm (18 it-lb)
Coolant hose clamp (32
- 48 2. 5 Nm (22 in-lb)
mm hose diameter)
Radiator drain plug to radiator 2
- 3 Nm (18 - 27 In-lb)
Thermostat cover to
coolant pump 10 Nm (89 in-lb)
Coolant pump, replacing (6-cylinder
models)
< The engine coolant pump is mounted in the front of the en-
gine in the timing chain cover.
- Drain cooling system as described earlier. See Coolant,
draining and filling (6-cylinder models).
WARNING-
Allow cooling system to cool before opening or draining sys-
tem.
- Remove cooling fan and fan shroud. See Mechanical (vis-
cous clutch) cooling fan, removing and installing.
- Remove coolant pump drive belt. See 020 Maintenance.
4 Remove coolant pump pulley bolts (arrows) and remove pul-
ley from pump.
- Remove nuts retaining pump to engine block.
NOTE-
The coolant pump is mounted on studs and retained by nuts.

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.," --
Radiator and Cooling System --- 1
insert two M6 screws (arrows) in tapped bores and tighten
uniformly until pump is free from timing chain cover (thermo-
stat and hoses have been removed for purposes of visual
clarity).
Installation is reverse of removal, noting the following:
Be sure to replace sealing O-ring and gaskets.
Coat O-ring with water-based lubricant during installation.
Refill with coolant. See Coolant, draining and filling
(6-
cylinder models).
Tightening torques
-
Coolant pump to timing chain 10 Nm (89 in-lb)
cover
Coolant pump pulley to coolant
10 Nm (89 in-lb
pump
Engine block drain plug to block 25 Nm (1 8 It-lb)
Radiator drain plug to radiator 2 - 3 Nm (I8 - 27 in-lb)
Coolant pump, replacing (V-8 models)
I 1 < The engine coolant pump is mounted in the front of the en-
gine in ;he timing chain cover.
1. Thermostat housing
2. Thermostat
3. Thermostat sealing O-ring
4. Water pump
5. Water pump gasket
- Drain cooling system. See Coolant, draining and filling (V-
8 models).
- Remove cooling fan and fan shroud. See Mechanical (vis-
cous clutch) cooling fan, removing and installing.
- Remove engine drive belts: See 020 Maintenance.
NOTE-
Mark direction of drive belt rotation if reusing belt,
- Remove vibration dampener. See 117 Camshaft and Tim-
ing Chain.
- Disconnect mass air flow (MAF) sensor electrical harness
connector. Remove air intake duct together with
MAF sensor.
- Disconnect coolant hoses from thermostat housing and cool-
ant pump housing.

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. --
Radiator and Cooling system/
4 Pry out expansion rivets (A) on left and right side of fan
shroud. Loosen hose clamp
(6) and remove hose from ex-
pansion tank.
Remove expansion tank: Remove expansion tanlc cap, vent plug
(A) and tank retain-
ing clips (arrows).
Lift expansion
tanlc upward and off lower retaining lugs.
Push shroud back to expose expansion tank vent line. Re-
move line.
Using 32 mm wrench
(BMW special tool 11 5 040) on fan
clutch nut (arrow), turn wrench in a clockwise direction
(working from front of car) while counterholding pulley with
BMW special tool 11 5 030. Spin fan off coolant pump.
NOTE-
The radiator cooling fan nut (32 mrn wrench) has left-hand
threads.
Disconnect electrical harnesses from
AUC (air quality) sen-
sor and coolant level sensor.

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--
Radiator and Cooling System 1
4 Lift fan and shroud together out of engine compartment.
- Detach upper and lower radiator hoses.
NOTE -
Later models use retaining clips to fasten coolant hoses to
expansion tank and radiator.
- Disconnect temperature sensor harness connector.
4 Remove radiator support bolts and supports (arrows). 6-cyl-
inder shown.
- Slide right side of radiator back toward engine and pull radi-
ator up to remove.
- Installation is reverse of removal, noting the following:
Fill radiator and cooling system. See Coolant, draining
and filling (6-cylinder models) or Coolant, draining
and filling (V-8 models).
Tightening torques
Engine block drain
plug to block 25 Nm (18 it-lb)
Radiator drain plug
to radiator 2 - 3 Nm (18 - 27 in-ib)
Expansion tank, removing and installing
- Raise front of car and support safely.
WARNING -
Make sure the car is stable and well supported at all times.
Use a professional automotive
/iff orjacltstands designed for
the purpose. A
floorjacl~ is not adequate support.
- Remove splash shield from under engine.
- Drain radiator as described earlier. See Coolant, draining
and filling (6-cylinder models) or Coolant, draining and
filling
(V-8 models).
I WARNING-
Allow cooling system to cool before opening or draining sys-
I tem.