2001 BMW 525i air flow

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Cylinder Head Removal and Installation
- Install exhaust manifolds using new gaskets and nuts. Coat
manifold studs with copper paste prior to installing nuts.
Tightening torque Exhaust
maniiold to cylinder head (M7)
20 Nm (15 ft-lb)
- Install electrical harness connectors for oil pressure sender
and coolant temperature sensor before installing
intalte man-
ifold.
7 Install intake manifold:
1. Manifold mounting nuts: tighten to 15 Nm (1 1 ft-lb)
2. Fuel pipe bracltet
3. Fuel pipe bracltet
4. Vacuum pump bracltet
5. Manifold mounting bracltet
6.
Tank venting valve bracltet
7. Mounting bracket to manifold bolt (M6)
8. Mounting bracket to cylinder block nut (MIO), tighten to
47 Nm (33 fi-lb)
Intake manifold installation is reverse of removal, noting the
following:
* Use new fuel injector seals.
Carefully
check intake manifold gasket and replace if nec-
essary.
Inspect O-ring seal between mass air flow sensor and air
filter housing. To facilitate reassembly, coat seal with
acid-
free grease.
Use new fuel injector seals.
Carefully check intake manifold gasket and replace if
necessary.
CA UTIOPI-
When reattaching throttle assembly harness connector, con-
nector is fully tightened when arrows on connector
andplug
line up.
Tightening torque
lntalte manifold to cylinder
head (M7)
15 Nm (1 1 it-lb) ~ ~- Mounting bracket to cylinder bloclt (M10) 47 Nm (33 ft-lb)
Mounting bracket to intake manifold (MI?) 10 Nm (89 in-lb)

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Cylinder Head Removal and Installation /
4 Remove top engine cover by releasing quick release fasten-
ers (arrows) by pressing down.
NOTE-
Earlier models may have an engine cover with pry off caps
and fasteners
In place of quick release fasteners.
4 Remove left and right interior ventilation ducts (left side
shown):
- Release locking tabs (A) or locking strap (early models, not
shown).
Release spring lock (B).
* Rotate duct inward (arrow) to remove.
Disconnect electrical harness from hood light switch (C).
Release locking clip and remove ventilation housing cover
(D).
Lift out housing from inner fender.
- Removal of right side ventilation housing is similar.
4 Air filter housing assembly, removing:
Disconnect electrical harness connectors from mass air
flow sensor (A) and temperature sensor (B).
Loosen hose clamp (C).
Remove filter housing mounting fastener (arrow) and re-
move filter housing with mass air flow sensor.

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-. .
Cylinder Head and Valvetrain -- v . -- --- --
4 Remove air filter housing and ducts:
Loosen hose clamps as necessary and disconnect electri-
cal harnesses.
- Remove air filter housing mounting fastener (arrow).
Loosen hose clamp at throttle body.
Remove air filter housing with mass air flow sensor and
duct.
Disconnect the following electrical harness connectors.
Knoclc sensors (A).
Thermostat housing (B).
Throttle position sensor/throttle position switch and idle
valve
(C).
Camshaft position sensor (D).
* Ignition coils (E).
Remove mounting nuts (arrows)
ducting. from
wiring harness

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Camshaft Timing chain1
- Disconnect negative cable (-) from battery.
CAUTION-
Prior to disconnecting the battery, read the battery discon-
nection cautions given
in 001 General Cautions and
Warnings.
4 Removing top and side engine covers:
Press down on locking pins (arrows) to release locks. Lifl
intake manifold cover straight up to remove.
Pry out caps from side covers.
Remove fasteners
and covers.
NOTE-
Some early models use
pry out trim caps and fasteners to
hold the top cover in place.
Disconnect electrical harness connectors at ignition coils
(A).
Remove left and right side ignition coil mounting fasteners
and coils.
NOTE-
Make note of location of ground strap (arrow).
Remove spark plugs.
- Remove posltlve (+) terminal cable from left cylrnder head
cover.
- Unbolt left and right side cable ducts from fuel rail
Remove air filter housing and mass air flow sensor:
Disconnect mass air flow sensor and intake air tempera-
ture sensor electrical harnesses
(A and B).
Remove air filter housing mounting fastener (arrow)
Loosen intake hose clamp
(C).
Remove air filter housing with mass air sensor and intake
duct from throttle body assembly.

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Camshaft Timing chain/
Camshaft timing, checking and adjusting
(M62 engine)
WARNING -
Allow engine to cool before beginning this procedure. 1
- Working inside luggage compartment, disconnect negative
battery cable.
CAUTIOI\C
Prior to disconnecting battery cable, read the battery discon-
nection cautions given
in 001 General Cautions and
Warninss.
4 Removing plastic top covers:
Press down on locking pins (arrows) to release locks. Lift
intake manifold cover straight up to remove.
Pry out caps from side covers.
Remove fasteners from beneath
caDs. Lift off covers.
4 Remove air filter housing and ducts:
Disconnect mass air flow sensor and intake air tempera-
ture sensor electrical harnesses
(A and B).
Remove air filter housing mounting fastener (arrow).
Release hose clamp at intake air duct on base of air filter
housing.
Loosen intake hose clamp
(C) and release hose from
mass air flow sensor.
Remove hose at idle air stabilizer.
Release hose clamp at throttle body and remove hose.
Remove upper air filter housing with mass air flow sensor.
- Unbolt left and right side cable ducts from fuel rail.

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... . . Lubrication sy=
Upper oil pan, removing and installing (V-8)
The engine oil pan removal procedure requires that the en-
gine be supported from the top and the front suspension
sub-
frame be lowered.
- Disconnect negative (-) battery cable
4 Lift hood into assembly position.
- While supporting hood, disconnect support struts.
Open hood
fully and lock in piace by installing bolts
(arrow) in left and right hinges to lock hood in place
4 Remove engine top cover:
- Early version: Pry off caps (arrows) and remove fasteners.
Late version: Depress fasteners (arrows) and lift cover.
4 Remove air filter housing and mass air flow sensor:
Disconnect mass air flow sensor
(A) and intake air temper-
ature sensor
(B) electrical harness connectors.
Remove air filter housing mounting fastener (arrow)
Loosen
intake hose clamps (C and D).
Remove air filter housing with mass air flow sensor.
Remove intake hose from throttle body.

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I Ignition System
Camshaft position sensors
The camshaft position sensors are used by the englne man-
agement system for VANOS control, sequential fuel injection
and knock control.
Intake camshaft position sensor, replacing
(M52,M52 TU
and M54 engines)
- Make certain ignition has been turned off.
- Remove plastic cover from above fuel injectors by prying off
bolt covers and removing cover mounting bolts.
Remove complete air filter housing:
Disconnect electrical harness connector on mass air flow
sensor
(A).
Detach vacuum line at intake boot (B).
Loosen hose clamp at intake boot and detach air duct con-
nections
(C).
* Disconnect cold air duct tube (D).
Remove filter housing mounting screws (E).
- Disconnect harness connector from VANOS solenoid and
unscrew solenoid from VANOS control unit. Be prepared with
shop rags to catch oil released from VANOS unit.
Remove camshaft sensor (arrow) from
left front of cyl~nder
head, next to top of oil filter housing.
Disconnect camshaft sensor harness from under intake
manifold. Prior to removal, attach a stiff piece of wire to the
harness connector end to preserve proper routing of harness
for reinstallation.
Installation is reverse of removal, noting the following:
Use new O-rings when installing sensor and solenoid.
Be sure wiring is rerouted in same orientation.
Use scan tool to read out and clear
ECM fault memory
Tightening torques
-
Intake camshaft sensor to cylinder head 10 Nrn (7 ft-lb)
VANOS solenoid to VANOS control unit 30 Nm (22 ft-lb)

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120-15
Ignition system1
Exhaust camshaft position sensor, replacing
(M52 TU and M54 engines)
- Make sure ignition has been turned off.
4 Working at front of engine on exhaust (right) side, detach ex-
haust camshaft position sensor electrical harness connector
(arrow) and remove sensor.
- Installation is reverse of removal, noting the following:
Use a new O-ring when installing sensor.
- Use scan tool to read out and clear ECM fault memory.
Tightening torque
Exhaust camshaft sensor
to cylinder head 10 Nm (7 ft-lb)
Intake camshaft position sensor, replacing
(M62 and M62 TU engines)
- Make sure ignition has been turned off
4 Remove top engine cover by releasing quick release fasten-
ers (arrows) by pressing down.
4 Remove air filter housing and mass air flow sensor:
Disconnect mass air flow sensor and
intalte air tempera-
ture sensor electrical harnesses
(A and B).
Remove air filter housing mounting fastener (arrow).
Loosen hose clamps
(C and D).
Remove hose at idle air stabilizer.
Remove air filter housing with mass air flow sensor.
- Remove intalte hose from throttle body.