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170-25
Radiator and Cooling system]
< Disconnect expansion tank:
Remove expansion tank bleed screw and support clip
(A)
Loosen hose clamp (6) and disconnect coolant hose from
expansion tank.
Disconnect harness connector from coolant level sensor
(C).
Push top of expansion tank toward engine and disconnect
bleed hose.
Lift expansion
tank to free it from lower mounts, then lift
straight up to remove.
- Installation is reverse of removal, noting the following:
Fill radiator and cooling system as described earlier. See
Coolant, draining and filling (6-cylinder models) or
Coolant, draining and filling
(V-8 models).
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Page 523 of 1002

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180 Exhaust System
General Exhaust System
. . . . . . . . . . . . . . . . .
Exhaust system, removing and installing
Muffler, replacing..
. . . . . . . . . . . . . . . . .
Exhaust Manifolds . . . . . . . . . . . . . . .
Exhaust manifolds, removing
and installing (M52 engine)
. . . . . . . . . .
Exhaust manifolds, removing and
installing (M52
TU and M54 engines) . . .
Exhaust manifolds, removing
and installing (M62 engine)
. . . . . . . . . .
Oxygen Sensors. . . . . . . . . . . . . . . . . . . . 180-9
Oxygen sensors (precatalyst),
replacing
(M52 TU and M54) . . . . . . . . . . . . 180-9
Oxygen sensors (post-catalyst),
replacing (M52
TU and M54) . . . . . . . . . . . . 180-9
Oxygen sensor, replacing
(M52 and M62 engine) . . . . . . . . . . . . . . . 180-10
Exhaust System Diagrams . . . . . . . . . 180-1 1
M52 engine (528i 1997-1 998) . . . . . . . . . . 180-1 1
M52
TU and M54 engines
(528i 1999-2000 and 5251 2001-2003) . . . 180-1 2
M54 engine
(530i 2001-2003) . . . . . . . . . . 180-1 3
M62 engine
(540i 1997-1 998) . . . . . . . . . . 180-1 4
M62
TU engine (540i 1999-2003 . . . . . . . 180-1 5
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180-2
Exhaust System
The exhaust system is designed to be maintenance free, al-
though regular inspection is warranted due to the harsh oper-
ating conditions. Under normal conditions, the catalytic
converter does not require replacement unless it is damaged.
New fasteners, clamps, rubber mounts and gaskets should
be used when replacing exhaust components.
A liberal appli-
cation of penetrating oil to the exhaust system nuts and bolts
in advance may make removal easier.
WARNING -
The exhaust system and catalytic converter operate at
very high temperatures. Allow components to cool before
servicing. Wear protective clothing to prevent burns.
Do not use flammable chemicals near a hot
cataiyiic
converter.
Corroded exhaust system components crumble easily
and often have exposed sharp edges. To avoid injury,
wear eye protection and heavy gloves when working
Exhaust system, removing and installing
The removal and installation procedures given here are gen-
eral procedures for all models. The removal of the exhaust
system as a complete unit is recommended. Once the com-
plete system is removed from the car, individual pipes and
mufflers can be more easily replaced.
WARNING-
Exhaust gases are colorless, odorless, and very toxic. Run
the engine only in a well-ventilated area. Immediately repair
any
leaks in the exhaust system or structural damage to the
car body that
might allow exhaust gases to enter the passen-
ger compartment.
CAUTION-
Use care not to drag or bang oxygen sensors. Oxygen sen-
sors can be easily ruined.
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... .
Exhaust System
- With exhaust system fully cold, raise and support car for ac-
cess to exhaust system.
WARNING -
Do not worlc under a lifted car unless it is solidly supported on
jack stands designed for that purpose. Never work under a
car that is supported solely by a
jack.
- Disconnect oxygen sensor connector(s).
4 Loosen and remove bolts holding front exhaust pipes to ex-
haust manifolds (arrows). Right side of
V8 model shown.
- Support exhaust system
- Where applicable, disconnect exhaust support bracket as-
sembly from transmission.
< Remove hangers by prying off bracket (arrows).
- Lower exhaust system as a single unit to ground.
NOTE-
If the catalytic converterlfront exhaust pipe assembly is to be
replaced, transfer the oxygen sensors to the new
pipe(s).
Tightening torque
Oxygen sensor
55 Nm (41 ft-lb)
- installation is reverse of removal.
* Make sure there is at least 20 mm (314 in.) clearance be-
tween exhaust system and car body at every point.
Loosely install
ail exhaust system mounting hardware and
hangers before tightening fasteners to their final torque.
Coat manifold studs with copper paste before installing
nuts.
NOTE-
Where applicable, tighten front pipe with semi-flexible com-
pensator last when installing front pipe to
manifolds.
Tightening torques
Exhaust manifolds
to cylinder head 22 Nm (1 7 It-lb)
Front exhaust pipe to manifolds 30 Nm (22 ft-lb)
To prevent exhaust system rattles and vibration, the system
should be slightly preloaded by pushing the rear clamping
brackets forward about 7 mm (114 in).
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/Exhaust System Muffler, replacing
BMW offers individual mufflers as replacement parts for the
original one-piece assembly. Replacement of a rear muffler
may be possible with the system installed on the car. Re-
placement of the front or middle muffler should only be done
with the exhaust removed from the car.
< Mark length of new muffler pipe(s) on old system.
- Use exhaust pipe cutter to cut pipe(s). Deburr cut pipe
end@).
4 Use clamping sleeves to join new pipe(s) to old.
Make sure pipe ends are centered inside sleeve.
Point clamping sleeve bolt threads
(arrows) down.
- Reinstall exhaust system.
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Exhaust system1
Exhaust manifold removal procedures are organized accord-
ing to engine code. If necessary, see
100 Engine-General
for engine code and application information.
Exhaust manifolds, removing and installing
(M52 engine)
4 Exhaust manifolds for the M52 engine.
Always use new retaining nuts and gaskets when removing
and installing the exhaust manifolds.
- With exhaust system cold, raise and support car for access
to exhaust system.
WARNING -
Do not work under a lined car unless it is solidly supported on
jack stands designed for that purpose. Never work under a
car that is supported solely by a jack.
- Disconnect secondary air check valve and pipe from exhaust
manifold.
- Unbolt front exhaust pipe@) from exhaust rnanifold(s)
- Remove exhaust support bracket from transmission.
- Loosen and remove nuts from exhaust manifolds and remove
manifolds. Discard nuts and gaskets.
NOTE-
On cars with oxygen sensors mounted in the exhaust mani-
folds, use care when removing manifolds.
To be safe, remove
the sensors from the manifolds before removing manifolds.
- Installation is reverse of removal
Coat exhaust manifold mounting studs with copper paste
before installing new nuts.
Install manifold gaskets with arched side facing manifolds.
Tightening torque
Exhaust manifolds
to cylinder head 20 Nm (15 ft-lb)
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180-6
Exhaust System
Exhaust manifolds, removing and installing
(M52 TU and M54 engines)
I Exhaust manifolds with converters I 4 The exhaust manifolds incorporate the catalytic converters.
Two precatalyst and two post-catalyst oxygen sensors are
mounted in the exhaust manifold assembly.
Under normal conditions, the catalytic converters do not re-
quire replacement unless damaged. Always use new retain-
ing nuts and gaskets when removing and installing the
exhaust manifolds.
I\
1 4 Using engine support equipment (BMW special tools 00 0
200. 00 0 201. 00 0 202.00 0 204.00 0 208 or equivalent).
connect to
lifting eye on front of engine. Rhise engine approx.
/I 1
5 mm (IH in).
With exhaust system cold, raise and support car for access
to exhaust system.
WARNING-
Do not worlc undera liftedcar unless it is solidly supported on
jack stands designed for that purpose. Never worlc under
a
car that is supported solely by a jaclc.
in order to avoid damaging oxygen sensors:
- Detach oxygen sensor harness connectors,
Remove oxygen sensors from exhaust manifolds as de-
scribed later in this group.
Unbolt and remove secondary air
checkvalve and pipe from
right front of cylinder headlexhaust manifold.
Working underneath car, unbolt front exhaust pipes from ex.
haust manifolds.
With engine supported from above, remove right engine
mount
bracket and right engine mount (arrow).
Loosen and remove nuts from exhaust manifolds and remove
manifolds. Discard nuts and gaskets.
CA UTIOG
Take care tliat the front and rear oxygen sensor connectors
are not mixed up.
-