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General
Many of the maintenance and repair tasks in this manual call
forthe installation of new parts, orthe use of new gaskets and
other materials when reinstalling parts. Most often, the parts
that will be needed should be on hand before beginning the
job. Read the introductorytext and the complete procedure
to
determine which parts will be needed.
NOTE-
For some biggerjobs, partial disassembly and inspection is
required to determine a complete parts list. Read the proce-
dure carefully and, if necessary, male other arrangements to
get the necessary parts while your car is disassembled.
Genuine BMW parts
Genuine BMW replacement parts from an authorized BMW
dealer are designed and manufactured to the same high stan-
dards as the original parts. They will be the correct material.
manufactured to same specifications, and guaranteed to fit
and work as intended. Most genuine BMW parts carry a limit-
ed warranty.
Many independent repair shops make a point of using genu-
ine
BMW parts, even though they may at times be more ex-
pensive than parts from other sources. They know the value
of doing the job right with ihe right parts. Parts from other
sources can be as good as BMW parts, particularly if manu-
factured by one of
BMW's or~ginal equipment suppliers, but it
is often difficult to know.
BMW is constantly updating and improving their cars, often
malting improvements during a given model year. BMW may
recommend a newer, improved part as a replacement, and
your authorized dealer's parts department will know about it
and provide it. The BMW parts organization is best equipped
to deal with your BMW parts needs.
Non returnable parts
Some parts cannot be returned, even for credit. The best ex-
ample is electrical parts, which are almost universally consid-
ered non returnable. Buy electrical parts carefully, and be as
sure as possible that a replacement is needed, especially for
expensive parts such as electronic control units. It may be
wise to let an authorized BMW dealer or other qualified shop
confirm your diagnosis before replacing an expensive non re-
turnable
Dart.

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11 3-6
Cylinder Head Removal and Installation
- Disable ignition system by removing DME main relay. See
610 Component Locations for relay location.
WARNING-
. The ignition system produces high voltages that can be fa-
tal. Avoid contact with exposed terminals and use
exfreme
caution when working on a car with the ignition switched on
or the engine running.
Do not touch or disconnect ignition
components while
the engine is running or being cranked by the starter.
Failure to remove the DME main relay or attempting to
disa-
bie the fuel andignition systems by other methods may result
in damaoe to the enoine control module
(ECM).
- - Remove plastic cylinder head cover(s)
,,I . ,. .*,.,,&- - Remove coil grounding straps.
I CAUTION-
I nition system components. I
- Remove coils.
- Remove spark plugs from all cylinders.
NOTE-
Check the spark plugs for oil deposits that may indicate poor
cylinder sealing, then set them aside in order. Used spark
plugs should be reinstalled in the same cylinder from which
they were removed.
4 Install compression gauge in first cylinder spark plug hole,
tight enough to form a good seal.
- With parking brake set, transmission in PARK or NEUTRAL,
and accelerator pedal pressed to floor, crank engine with
starter. Record highest value indicated by gauge.
NOTE-
* The compression gauge reading should increase with
each compression stroke and reach near its maximum
reading in about
4-6 strokes.
All cylinders should reach maximum compression in the
same number of
strolces. If a cylinder needs significantly
more strokes to reach
maximum compression, there is a
problem.

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This group covers cylinder head and valvetrain service and
repair. Some of the repair procedures described here require
that the cylinder head first be removed as described in
113
Cylinder Head Removal and Installation.
NOTE- For timing chain and
VANOS repair information, see 117
Camshaft Timing Chain.
If it is
determined that the cylinder head will require signif-
icant reconditioning work, a remanufactured cylinder head
may be a good alternative. Remanufactured cylinder
heads are available from an authorized
BMW dealer.
The information given in this repair group is organized ac-
cording to engine code. For engine application information,
see
I00 Engine-General.
For specific repair procedures, refer to the appropriate repair
group:
* 020 Maintenance
100 Engine-General
113 Cylinder Head Removal and Installation
117 Camshafi Timing Chain
= 170 Radiator and Coo!ing System
Special Tools
Special BMW tools are required for most cylinder head ser-
vice described in this repair group. Many of these tools are ex-
pensive and only available through an authorized
BMW
dealer. If the special tools are not available, have the cylinder
head removed and disassembled by an authorized BMW
dealer. Be sure to read each procedure thoroughly before
starting a job to determine which special tools and equipment
will be necessary.
Most of the repairs to a cylinder head require precision
rna-
chine work to specific tolerances. This type of work should be
performed by an authorized BMW repairfacility or an ASE
certified machinist.
71 Torque wrench with flex shaft

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11 6-5
I Cylinder Head and valvetrain1
4 Timing chain tensioner bracket (V-8)
(Tool No. BMW
11 7 380)
CYLINDER HEAD
This section provides the specifications and special recondi-
tioning information necessary to repair the cylinder heads
covered by this manual.
The disassembled cylinder head should be inspected for
warpage and cracks. Check the valve guides and valve seats
for wear before machining a warped head. Always decarbon-
ize and clean the head before inspecting it.
Visually inspect the cylinder head for craclts.
If a cracked cyl-
inder head is suspected and no
craclts are detected through
the visual Inspection, have the head further tested for cracks
by an authorized BMW dealer or an ASE certified machinist.
A cracked cylinder head must be replaced.
NOJE-
When disassembling and inspecting the cylinder head, be
sure to
checlc the camshaft carrier bearing surfaces using a
straight edge for
warpage, and check the lifter bores for wear.
A high-quality straight edge can be used to
checlc for
warpage. A warpage of 0.05 mm (0.002 in.) is acceptable
without machining. A warped cylinder head can be machined
provided no more than 0.3
mm (0.012 in.) of material is re-
moved.
If further machining is required, the head should be
replaced. Removing more than this amount will reduce the
size of the combustion chamber and adversely affect engine
performance. A 0.3 mm
thicker head gasket for machined
heads is available from an authorized BMW parts depart-
ment.

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Cylinder Head and valvetrain1
While counter holding camshaft, remove exhaust camshaft
sprocket bolts
(arrows) from left cylinder head. Remove
sprocltets with chain.
< While counter holding camshaft, remove exhaust camshaft
sprocket bolts
(arrows) from right cylinder head. Remove
sprocltets with chain.
4 Use BMW special tool 11 3 430 to rotate camshaft into disas-
sembly position.
4 Loosen camshaft bearing caps nuts in correct sequence
(1-10) (left cylinder head shown).
NOTE -
Keep camshaft bearing caps in order. Used caps must not be
interchanged.
- Remove exhaust camshaft by repeating process.
0 Remove camshafts from cylinder head.
- Repeat camshaft removal process for right cylinder head.

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Table d. Valve guide specifications
Specifications
All engines (1997-2002)
Valve guide wear, maximum 0.5 mrn (0.020 in)
(valve tilt clearance
measured
with new valve)
Valve guide inside diameter,
installed
(tolerance per IS0 allowance H7)
Standard 6.0 mm (0.236 in)
Oversize
1 6.1 mrn (0.240 in)
Oversize 2 6.2
mm (0.244 in)
Valve stem oil seals
The purpose of the valve stem oil seal is to prevent excess oil
from entering the combustion chamber. The sign of faulty
valve stem oil seals is excessive oil consumption and smoke
from the exhaust immediately after starting and during decel-
eration.
NOTE-
Valve stem oil seals should not be reused. If valves are re-
moved, new valve stem oil seals should be installed.
Valve stem oil seal replacement requires that the cylinder
head be disassembled and the valves removed as described
above under Valves, removing and installing.
NOTE-
BMW special tools are available to remove the valve stem oil
seals. As an alternative, standard valve seal removal tools
are available from most automotive parts stores.
Lubricate new seal and install using hand pressure only. Be
sure to install valve spring
seat(s) before installing seal.

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... -.
Camshaft Timing chain1
Timing chains, removing
(M52 TU and M54 engines)
Camshaft timing chain removal requires that the oil pan be re-
moved. See
119 Lubrication System. Also required is re-
moval of the VANOS control
unit and disassembly of the
intake and exhaust camshaft sprocket assemblies as de-
scribed earlier in this repair group.
Special BMW
service tools are needed for timing chain re-
moval and installation. The special tools assure proper timing
of the valvetrain. Precise
marlts to set the timing on the cam:
shafts are not provided for reassembly. Read the procedures
through before beginning the job.
CA
UTION-
If the camshafts are not properly timed, the pistons can con-
tact the valves.
- D~sconnect negative (-) cable from battery.
CAUTION-
* Disconnecting the battery may erase fault code@) stored in
control module memory. Check for fault codes using spe-
cial
BMW diagnostic equipment.
Prior to disconnecting the battery, read the battery dis-
connection
cautfons given in 001 General Cautions
and
Warninqs.
- Remove VANOS control unit. See VANOS control unit, re-
moving
(M52 TU and M54 engines).
Remove sealing plug from crankcase below starter and se-
cure crankshaft with
BMW special tool ll 2 300.
Drain engine cooling system. See 170 Radiator and Cool-
ing System.
Remove belt driven cooling fan, fan shroud, and thermostat
housing. See
170 Radiator and Cooling System.
Remove drive belts. See
020 Maintenance.
NOTE-
Mark direction of belt rotation if reusing belt.
- Remove water pump pulley fasteners and pulley.
- Drain engine oil and remove oil pan as described in 119
Lubrication System.

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I Lubrication System -
- Remainder of assembly is reverse of disassembly.
Install flywheel, clutch or torque converter and
transmission.
Fill engine with oil.
- Run engine and check for leaks.
Tightening torques
Oil
drain plug fo oil pan (MI21 25 Nm (18 ft-lb)
Oil pan to engine
block
M6 (8.8 grade) 10 Nm (89 in-ib)
M6 (1 0.9 grade) 12 Nm (9 ft-lb)
M8 (8.8 grade) 22 Nm (1 6 it-lb)
Rear main seal carrier to crankcase
M6 10 Nm (89 in-lb)
ME 22 Nm (16 ft-lb)
Crankshaft rear main seal, replacing (V-8)
- Remove transmission. See 230 Manual Transmission or
240 Automatic Transmission.
- Manual transmission vehicles: Remove clutch pressure plate
and disc. See
210 Clutch.
- Remove flywheel. See 210 Clutch.
- Drain engine oil.
4 Remove bolts (A) retaining rear main seal carrier, including
bolts at (arrows) oil pan.
Carefully separate seal carrier from oil pan gasket and re-
move carrier.
CAUTION-
Do not damage oil pan gasket.
< Remove old seal and reinstall new seal into seal carrier using
) BMW special tools 11 1 230 and 00 5 500.