Page 232 of 1002

Downloaded from www.Manualslib.com manuals search engine
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.
Page 251 of 1002

Downloaded from www.Manualslib.com manuals search engine
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.
Page 258 of 1002

Downloaded from www.Manualslib.com manuals search engine
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.
Page 273 of 1002
Downloaded from www.Manualslib.com manuals search engine
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,
Page 279 of 1002

Downloaded from www.Manualslib.com manuals search engine
Camshaft Timing Chain
- Connect electrical harness connectors to camshaft position
sensors and VANOS solenoid valves.
- Remove BMW special locking tools from rear of cylinder
head.
- Remove cranltshaft locking tool and replace sealing plug.
Install intake camshaft baffle and cylinder head cover.
Checlc for correct seating of half-moon seals (A) in back of
cylinder head cover.
Use a small amount of Three Bond 1209
O or equivalent
sealant at corners
(B) of half-moon cutouts.
Similarly, seat gasket and
seal corners in front of cylinder
head, at VANOS control unit.
Tightening torque
Cylinder head cover to cylinder head
(M6) 10 Nm (89 in-lb)
- Remainder of installation is reverse of removal.
Tightening torques
Radiator fan (viscous clutch) to
coolant pump 40
Nm (30 ft-lb)
Spark plug to cylinder head
25 Nrn (18 ft-lb)
VANOS timing, checking and adjusting
(M52 TU and M54 engines)
Use this procedure to check and, if necessary, adjust cam-
shaft timing. This procedure assumes that the cylinder head
cover and intake
camshaft plastic baffle have been removed.
Also, be sure the cooling fan and the spark plugs have been
removed.
Remove primary camshaft chain tensioner cylinder
(arrow).
~~ ~ ~~ ~--~
CA UTlOAC
Primary camshaft chain tensioning piston is under spring
pressure.
Page 285 of 1002

Downloaded from www.Manualslib.com manuals search engine
-- - -- - -- Camshaft Timing chain1
- Remove camshaft locking tools from rear of camshafts
- Remove BMW special tool 11 4 220 (adjustable primary
chain tensioner). Reinstall primary chain tensioner.
Tightening torque Primary chain tensioner to cylinder head
70
Nm (52 it-lb)
- Remove crankshaft locking tool from transmission bellhous-
ing. Reinstall sealing plug.
- Remove VANOS setup bracket from front of cylinder head
- lnstall VANOS control unit as described earlier in this group.
- Remove compressed air fitting (BMW special tool 11 3 450)
from VANOS control unit.
- Fit VANOS oil line banjo bolt with new seals. Attach oil line to
VANOS control unit.
Tightening torque
Oil line to VANOS control unit (banjo bolt) 32 Nm (24 H-lb)
- Remainder of installation is reverse of removal, noting the fol-
lowing:
lnstall spark plugs.
* lnstall intake camshaft plastic baffle prior to installing cylin-
der head cover. lnstall ignition coil packs and connect elec-
trical harness connectors.
Install radiator cooling fan.
- lnstall air filter housing and top engine cover.
Tightening torque Radiator cooling fan
(VISCOUS clutch) to 40 Nm (30 ft-lb)
coolant pump
Cyitnder head cover to cylinder head 10 Nm (89 in-lb)
Sparlc plug to cylinder head 25 Nm (18 ft-lb)
Page 303 of 1002

Downloaded from www.Manualslib.com manuals search engine
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.
Page 304 of 1002
Downloaded from www.Manualslib.com manuals search engine
1 17-68
Camshaft Timing Chain
4 Remove left and right side ignition coils and spark plugs:
- Remove positive (+) terminal cable from left cylinder head
cover.
- Unbolt lefl and right side cable ducts from fuel rail,
4 Disconnect fuel injector electrical connectors:
Pry corner of wire lock clip to release connector from injec-
tor
(arrow).
Repeat for all injectors.
Lift off wiring ducts.
4 Remove Fasteners (arrow) from lefl and right cylinder head
cover fasteners and remove covers.