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General
Table a. General bolt tightening torques in Nm
(max. permissible)
Bolt Class (according to DIN
267)
Gaskets and seals
Gasket aredesigned to crush and become thinner as the mat-
ing parts are bolted together. Once agasket has been used, it
is no longer capable
;f malting as good a seal as when new,
and is much more likely to leak.
Forthis reason, gaskets
should not be reused.
Some gaskets and seals are
d~rectional. Make sure thatthese
are
~nstalled correctly. In places where a shaft must pass
through a housing,
flex~ble lip seals are used to keep the lubri-
cating
011 or grease from leaking out past the rotatlng shaft.
Seals should never be reused once they have been removed.
When
rernovlng a seal, be careful not to damage the metal
surfaces.
The ltey to seal installation is to get the seal in straight without
damaging it. Use a seal driver that is the same diameter as
the seal housing to gently and evenly install into place.
If a
proper size seal driver is not available, a socket of the right
size will do.
Some seals are directional and special installation instruc-
tions apply. Make sure a seal is installed with the lip facing the
correct way. Note the installation direction of the old seal be-
fore removing it.
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Engine-General
This section covers system descriptions and general informa-
tion on engines and engine management systems. Also cov-
ered is basic engine troubleshooting.
For specific repair procedures, refer to the appropriate repair
group:
110 Engine Removal and Installation
0 113 Cylinder Head Removal and Installation
116 Cylinder Head and Valvetrain
0 117 Camshaft Timing Chain
119 Lubrication System
120 Ignition System
130 Fuel Injection
0 170 Radiator and Cooling System
E39 models are fitted with a variant of either an inline 6-cylin-
der or a
V-8 engine. See Table a.
Table a. Engine specifications
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11 3-2
Cylinder Head Removal and Installation
This group covers cylinder head removal and installation as
well as cylinder
headlvalve diagnostic procedures.
In the procedures in this repair group, engines are referred to
by engine code. If necessary, see
100 Engine-General for
engine code and application information.
The information given in this repair group assumes that the
engine is installed in the engine bay. On the
6-cylinder en-
gines, the VANOS control unit must be removed in orderto re-
move the cylinder head from the engine block. On
M52TU
and M54 engines, camshafts must be removed from the cylin-
der head before the head is removed.
The cylinder head removal and installation procedures for the
M62 V-8 are also included, butthe proceduresforthe M62TU
V-8 with VANOS are not provided.
For cylinder head and valvetrain reconditioning information,
see
116 Cylinder Head and Valvetrain.
For specific repair procedures, refer to the appropriate repair
group:
020 Maintenance
116 Cylinder Head and Valvetrain
117 Camshaft Timing Chain
170 Radiator and Cooling System
610 Component locations
NOTE-
If a head gasket problem is suspected, a compression test or
leak-down test will usually detect the fault See Diagnostic
Testing later
in this group.
Special tools
Special BMW service tools are required to properly remove
and install the cylinder head on engines covered by this man-
ual. The special tools are used to time the valvetrain to the
crankshaft, and to remove the VANOS control unit, the cam-
shafts and the
Tom (El2) head bolts. Read the entire proce-
dure through before beginning the job.
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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 6-6
Cylinder Head and Valvetrain
4 Before machining the head to correct for warpage, measure
the total height
(A) (thickness of the cylinder head). Minimum
height specifications are given in Table a. Cylinder head
height.
NOTE-
6 cylinder and V-8 engines share cylinder head height spec-
ifications.
Table a. Cylinder head height
New Minimum height
(A)
140.0 rnrn (5.512 in.) 139.7 rnrn (5.500 in.)
Valves, leak test
To test the valves for leakage, the cylinder head must be dis-
assembled with camshafts and camshaft carriers removed.
With valve assemblies and spark plugs installed, place the
cylinder head on a workbench with the combustion chamber
facing upward. Fill each combustion chamber with a thin non-
flammable liquid. After fifteen minutes, check the level of the
fluid. If the fluid level in any cylinder drops, that cylinder is not
sealing properly.
Camshaft wear
Camshaft wear is usually caused by insufficient lubrication.
Visually inspect camshaft lobes and journals for wear. Cam-
. ~~ shaft wear specifications are given in Table b. Camshaft
wear specifications.
CA UTIOI\C
If the camshaft is being replaced due to cam lobe wear, it is
recommended that the corresponding lifters should also be
replaced to avoid damaging the new camshaft
Table b. Camshaft wear specifications
6 cylinder engines V-8 engines
Axlal play 0.150-0.330 rnrn 0 200-0 360 rnrn - .-
(0.0060-0 013 in.) (0.008 - 0.014 in ) - - Radlal play 0.020-0.054 rnrn 0.040-0.074 rnrn
(0.0008-0.0021 in.) (0.016 - 0.029 in.)
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Cylinder Head and valvetrain1
Hydraulic lifters, checking and replacing
Self-adjusting hydraulic lifters (A) keep the valve clearances
within a limited working range. Hydraulic lifters are sealed
units and require no maintenance. Section view of camshaft
(6) and valve with conical valve spring (C) shown.
Under some circumstances, such as a cold start, the cam fol-
lowers may emit noise. Hydraulic lifter noise is usually a
high-
pitched tapping or chattering noise. In most instances, this is
considered normal as long as the noise goes away in a few
minutes (maximum
20 minutes). If the noise does not go
away, either the lifter is faulty or the oil pressure to the lifter is
low. Hydraulic lifter replacement requires that the camshaft
first be removed.
NOTE-
Before checking hydraulic lifters, male sure engine oil is
fresh and at the proper level.
Sticky lifters can be the result of
sludge build up in the cylinder head and lifters.
- Run engine until it reaches normal operating temperature.
Shut off engine.
- Working inside luggage compartment, disconnect negative
battery cable.
CAUTION-
Prior to disconnecting battery cable, read the baltery dls-
connection cautions given In 001 General Cautions and
Warnings.
Disconnecting the battery may erase fault
code(s)
stored in control module memory Check for fault codes
4 Remove left and right interior ventilation duct (left side
shown):
Release plastic locking tab
(A) or release loclting tabs on
top of duct (later models).
Rotate duct counterclockwise to
unloclt from bulithead and
remove (arrow).
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Cylinder Head and Valvetrain
< Remove oil baffle cover from above intake camshaft(s)
- Rotate engine at crankshaft vibration damper center bolt in
normal direction of rotation (clockwise) until camshaft lobe of
lifter to be tested points away from the lifter, allowing valve to
be completely closed.
Use a plastic or wooden stick to press down on top of lifter
with approximately 3.5 Nm
(2.25 ft-ib) of force.
If the lifter collapses slightly as though spring loaded, air
may be trapped in the lifter.
NOTE-
Air trapped in hydraulic lifters may result from oil foaming (air
being drawn
in by the oil pump). This may be caused by a
faulty oil pump control valve O-ring; leaking oil pump pickup
gaslcet; or by oil starvation to pump.
Press down on top of lifter for
10 to 15 seconds uslng approx-
lmately 6 to 9 Nm (4.5 to 6.75 ft-lb) of force.
If anv clearance is created between the lifter and the
cam-
shafi lobe, the check valve in the lifter is not closing. Re-
place lifter.
- To replace a hydraulic lifter, remove appropriate camshaft.
Refer to camshaft removal procedures given in Camshaft
and lifter removal and installation.
Once camshaft is removed, withdraw faulty
lifter(s) and re-
place with new
lifter(s). Inspect lifter bores for wear and scor-
ing at arrows.
- Reinstall camshafts. See Camshaft and lifter removal and
installation.
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1 16-56
Cylinder Head and Valvetrain
This section covers valve removal and reconditioning, includ-
ing valve guides, seats, springs, and valve stem oil seals.
Valves, leak test
To test the valves for leakage, the cylinder head must be dis-
assembled with camshafts and camshaft carriers removed.
With valve assemblies and spark plugs installed, place the
cylinder head on a workbench with the combustion chamber
facing upward. Fill each combustion chamber with a thin non-
flammable liquid. After fifteen minutes,
check the level of the
fluid. If the fluid level in any cylinder drops, that cylinder is not
sealing properly.
Valves, removing and installing
- Remove cylinder head as described in 113 Cylinder Head
Removal and Installation.
CAUTIOI\C
(M52 TU/M54 engines only) Do not let the hydraulic lifters
fall out as the camshaft carrier is removed. Special suction
cups are available from
BMW to hold the hydraulic lifters in
place during carrier removal.
* Hydraulic cam lifters should be stored m an uprfght po-
sition. If necessary, use a magnetic tool to
aidin remov-
al of the lifters.
- Remove valves using a valve spring compressor.
CAUTIOI\C
Label each valve assembly as it is removed so it can be in-
stalled in its original position.
-
- Remove and discard valve stem oil seals from valve guides.
See Valve stem oil seals later in this section.
- Valve installation is reverse of removal. Remove carbon de- - -
posits from the valves using a wire brush or wire wheel. -
-
Valve specifications are listed in Table c. Valve specifica-
tions.