2001 BMW 525i ignition coil ground

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11 3-73
Cylinder Head Removal and Installation /
1
- Remove viscous clutch cooling fan. See 170 Radiator and
i Cooling System. i i I 4 Remove ignition coil fasteners and coils (noting location of
~ ground strap).
1
Remove sparlc plugs.
i
Remove oil distribution tube fasteners and remove tubes
from both cylinder heads.
4 Using crankshaft center bolt, turn crankshaft cloclcwise until
number one cylinder (front cylinder right side) is in
TDC (ar-
rows).

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I Cylinder Head and Valvetrain
- Remove adjustable primary timing chain tensioner tool and
reinstall primary chain tensioner cylinder to cylinder head.
Tightening torque
Primary chain tensioner cylinder
to 70 Nm (52 ft-lb)
cylinder head
- Remove flywheel locking tool from crankcase. Replace spe-
cial tool bore sealing plug.
- Remove camshaft locking tools from cylinder head
Install intake camshaft cover and cylinder head cover.
Check for correct seating of half-moon seals (A) in back of
cylinder head cover.
Use a small amount of Three Bond
8 1209 or equivalent
sealing compound at corners
(B) of half-moon cutouts.
Seat gasket and seal corners at VANOS unit with Three
Bond
@ 1209.
Tightening torque Cylinder head cover to cylinder head
(M6) 10 Nm (89 in-lb)
- Installation of the remaininq parts is reverse or removal, not- -
ing the following:
Change engine
011 and f~lter as descr~bed in 020 Mainte-
nance.
Reconnect battery.
To prevent damaging the engine electronic systems, install
all ground wire previously removed, including the ground
wires for the ignition coils.
Tightening torque
-
Radiator cooling fan to coolant pump 40 Nm
(30 ft-ib)
Spark plug to cylinder head
25 Nm (18 ft-ib)

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Cylinder Head and Valvetrain
< Disconnect fuel injector electrical connectors from injectors.
Pry corner of wire lock clip (arrow) on first injector.
* Repeat for all injectors.
Lift wiring ducts off and set aside.
4 Remove right and left side ignition coil mounting nuts (ar-
rows) and coils.
NOTE-
Male note of location for ground straps (arrow A).
- Remove spark plugs.
- Disconnect positive (+)jumper junction from top of lefl cylin-
der head cover.
4 Remove retaining nuts (arrows) and remove oil lines from
left and right cylinder heads.

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Camshaft Timina chain1
- Remove viscous clutch cooling fan. See 170 Radiator and
Cooling
System.
CA UTlOEIC
The radiator cooling fan nut (32mm wrench) has left- hand
threads.
.
< Remove engine trim covers:
Pry out plastic trim caps (arrows).
. Remove cover fasteners and covers.
4 Remove ignition coils:
0 Disconnect ignition coil electrical harness connectors
Remove
coil mounting fasteners and remove coils.
Remove spark plugs.
NOTE-
Make note of ignition coil ground strap locations.
Disconnect VANOS electrical harness connector
(A) and oil
line fitting
(B) from VANOS control unit.
NOTE-
Wrap the VANOS oil line fitting with a shop rag to absorb
leaking oil.
- Disconnect cranltcase breather by squeezing at arrows,
- Remove cylinder cover mounting fasteners and remove
cylinder head cover.
NOTE-
The cylinder head cover mounting bolt insulators and gas.
kets should be reinstalled in their original positions. Make
note of their arrangement during removal.

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Camshaft Timing Chain
VANOS timing, checking and adjusting
(M52 engine)
NOTE-
* Special BMW service tools are required to remove and in-
stall the VANOS control unit. Read the procedure through
before starting the job.
If the camshafts are not properly timed, the pistons can
contact the valves.
- Disconnect negative (-) cable from battery.
CAUTIOG Disconnecting the battery may erase
faultcode(s) storedin
control module memory. Prior to disconnecting the battery,
checlc for fault codes using special BMW diagnostic equip-
ment.
Prior to disconnecting the battery, read the battery dis-
connection cautions given in
001 General Cautions
and Warnings.
- Remove viscous clutch cooling fan. See 170 Radiator and
Cooling
System.
CAUTIOG The radiator cooling fan nut
(32 mm wrench) has left-hand
threads.
4 Remove ignition coils:
Disconnect ignition coil electrical harness connectors.
Remove coil mounting fasteners and remove coils.
Remove
spark plugs.
NOTE-
Make note of ignition coil ground strap locations.

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Camshaft Timing Chain
VANOS control unit, removing
(M52 TU and M54 engines)
This procedure includes removal of the Double VANOS con-
trol unit.
NOTE-
If the Double VANOS control unit is being replaced, camshaft
timing must be checked. This procedure requires multiple
special tools. Be sure to read the procedures through before
beginning the repair.
- Working inside luggage compartment, disconnect negative
(-) battery cable.
Prior to disconnecting the
batteg read the battery discon-
nection cautions given in
001 General Cautions and
Remove engine cooling fan assembly. See 170 Radiator
and Cooling System.
Remove engine trim covers.
Pry out plastic trim caps (arrows).
Remove cover fasteners, oil filler cap, and covers.
Remove ignition coils:
Disconnect ignition coil electrical harness connectors.
Remove coil mounting fasteners and coils.
NOTE-
Make note of ignition coil ground strap locations.
Remove spark plugs,

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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 Timina Chain
< Remove cylinder head cover sealing gaskets from lefl cylin-
der head cover. Install
BMW special tool 11 1 412 into gasket
groove of cylinder head cover.
Install lefl cylinder head cover. Fit cylinder head cover re-
taining nuts to cylinder head cover studs at cylinders
5 and
6 (first two cylinders on left side cylinder bank).
Tighten nuts uniformly in
'I2 turn steps
Tightening torque
Timing case cover to head
15 Nm (1 1 ft-lb)
- Remove special tool 11 1 41 2 and install new gaskets to cyl-
inder head cover:
Clean gasket groove and install new gasket.
Apply Three Bond
12098sealant tojoint between cylinder
head and timing cover and at half-moon shaped cut-outs.
Tighten cylinder head cover nuts.
Tightening torque Cylinder head cover to head
I5 Nm (1 1 ft-lb)
- Remainder of installation is reverse of removal, noting the fol-
lowing:
Where applicable remove protective film from gaskets.
Use new gaskets when mounting intake manifold. Tighten
nuts finger tight first, then torque to specification in stages
worlting diagonally from center out.
Ground straps for ignition coil harnesses are at cylinders
no.
3 and no. 7. See 120 Ignition System.
Refill and bleed cooling system as described in
170 Radi-
ator and Cooling System.
Change engine oil and filter as described in
020 Mainte-
nance.
CAUTIOI\C
To prevent damaging engine electrical systems, be sure to in-
stall ail ground wires previously removed.