1999 BMW 528i exhaust

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Camshaft Timing Chain
1 VANOS I 4 When engine is started, camshafts are in deactivated
camshaft
retarded Engine I i oil supply
position:
. lntalte camshaft is held in RETARDED position by oil
pressure.
Exhaust camshaft is held in ADVANCED position by
preload spring and oil pressure.
VANOS
Piston out
ECM Piston in Within 2
- 5
seconds (50 engine revolutions), the ECM begins
monitoring and controlling camshaft positions.
The Double VANOS system allows full variability of camshaft
timing up to the limits of the system. When the ECM detects
that the camshafts are in optimum position, the solenoids are
modulated at approximately 100
- 220 Hz to maintain oil pres-
sure on both sides of the actuator pistons to maintain timing.
In models with DME
MS 43.0 (model year2001 and newer),
the engine control module (ECM) detects camshaft position
before the engine starts, thereby adjusting camshaft timing
immediately upon start-up.
NOTE-
. VANOS system troubleshooting and diagnostics is best
accomplished using a scan tool.
. Diagnostic Trouble Codes (DTCs) pertaining to the
VANOS system are listed
in the following table. See also
OED On-Board Diagnostics.
Elevated oil temperatures can cause VANOS to deactivate.
Oil that is too thick (high viscosity) may cause
a DTC to be
set
in the ECM. If VANOS is deactivated (limp-home
mode), there will be a noticeable loss of power.
VANOS fault codes
BMW code P-code Fault description
19
PI529 VANOS solenoid valve activation,
exhaust
21
PI525 VANOS solenoid valve activation,
intake
103
PI519 VANOS faulty reference value
intake
104
PI520 VANOS faulty reference value
exhaust
105
PI522 VANOS stuck (Bank I) intake
106
PI523 VANOS stuck (Bank 2) exhaust

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1 17-36
Camshaft Timing Chain
1 Double VANOS control unit
1. BoltM6
2. Exhaust camshaft position
sensor
3. Sealing ring
4. Camshaft end sealing plug
-tighten to 50 Nm (37 ft-lb)
5. Camshaft seal cap
6. VANOS hydraulic piston set
screw -CAUTION: left hand
thread -tighten to
10 Nm
(89 in-lb)
7. Nut M7 -tighten to
14 Nm
(1 0 ft-lb)
8. Engine lifting hook
9. Stud M7
10. Nut
M6 -tighten to 10 Nm
(89 lb-in)
11. Gasket
12. Cylinder head
13. Sealing ring
14. Intake camshaft sensol
15. Bolt M6
16. VANOS control unit
17. Copper sealing ring
18. VANOS oil feed line
19. Banjo bolt -tighten to 32 Nm
(24ft-lb)

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11 7-38
[Camshaft Timing Chain
4 Disconnect electrical harness connector (A), oil line fitting
(B), and cranltcase vent tube (squeeze at arrows).
NOJE-
Oil will drain from VANOS unit fitting. Use shop rags to keep
oil off drive belts.
- Remove cylinder head cover fasteners, and cover.
4 Remove oil baffle cover from intake camshaft
4 D~sconnect electrical connections from exhaust camshaft po-
sition sensor and VANOS control valve (arrows).
4 Using banjo bolt from VANOS control unit oil line, install test
fitting
(BMW special tool 11 3 450) to VANOS control unit.

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11 7-39
Camshaft Timing Chain
4 Cover oil hole in VANOS control unit (arrow) with shop towel
to capture oil which will spray when compressed air line is
connected.
- Connect compressed air line to air fitting. Apply air pressure
set to
2 - 8 bar (30 - 110 psi).
4 With compressed air line connected, turn engine clocltwise
using crankshaft center bolt at least two rotations, until cylin-
der
1 is at (TDC) position (intake and exhaust carnshafl lobes
as shown arrows).
Do not rotate engine
countercloclwise to reach the top dead
centerposition. Instead, complete another two complete
Remove sealing plug from bore under starter. Lock
crank-
shafl in TDC position with BMW special tool 11 2 300
(arrow).
-
4 Unscrew and remove threaded studs (arrows) at rear of
cylinder head.

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. .. ~-
Camshaft Timing Chain -
4 Secure camshafts in TDC position using BMW special tool
set
11 3 240.
- Disconnect compressed air line, leaving compressed air fit-
ting attached to VANOS control unit.
NOTE -
Oil will drain from pressure line. Have a container and rags
ready
4 Unscrew sealing plugs from VANOS control unit (arrows).
NOTE-
Oil will drain from sealing plug bores. Have a container and
rags ready
4 Pull sealing caps straight out of VANOS control unit with
BMW special tool 11 6 170, or with short nose pliers.
NOTE-
Additional oil may drain from VANOS control unit.
4 Remove set screws (left-hand thread) on ends of intake and
exhaust camshafts.
NOTE-
Set screws have left hand threads. Remove with a clockwise
motion.

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I Camshaft Timing Chain
- Using new gasket, install VANOS control unit to cylinde~
head.
Reinstall engine support eye.
Tightening torques VANOS control unit to cylinder head
M6 nut 10 Nm (89 in-lb)
M7 nut 14 Nm (10 ft-ib)
4 Insert and tighten VANOS hydraulic piston set screws on
intake and exhaust camshafts.
CAUTIOI\C
Set screws have left hand thread Tighten counterclocltwise.
Tightening torque
Hydraulic piston
to splined shaft 10 Nm (89 in-lb)
(set screw)
4 Replace sealing caps inside VANOS control unit with BMW
special tool 11 6 170, or short flat nosed pliers.
Insert and secure VANOS sealing plugs (arrows), using new
sealing O-rings.
Tightening torque Sealing plug to VANOS control unit 50 Nm (37
it-lb)
Remove compressed air fitting 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
it-lb) -

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Camshaft Timing chain1
< With compressed air line connected, turn engine at least
twice in direction of rotation until cylinder
1 intake and ex-
haust camshaft lobes (arrows) face each other.
Do not rotate engine counterclockwise to reach the top dead
center position. Instead, complete another two complete ro-
Remove sealing plug from bore at bellhousing. Secure crank-
shaft in
TDC position with BMW special tool 11 2 300 (ar-
row).
- Remove cylinder head cover studs at rear of cylinder head.
< Place BMW special tool 11 3 240 over camshafts ends and
measure clearance of tool to cylinder head surface.
NOTE-
If the exhaust side of the tool (A) is not flush with the head,
adjust camshaft timing as described below.
Due to flexible sprocket design and VANOS control unit tol-
erances and play, the
intake side of special tool 11 3 240
(B) may be up to 1 mm (0.04 in) above the surface of the
cylinder head. This is normal. Reassemble engine. Other-
wise, adjust camshaft timing as described below.
- Remove double VANOS control unit. See VANOS control
unit, removing
(M52 TU and M54 engines).
< Press down on secondary chain tensionerand lock into place
using BMW special tool
11 3 292 or equivalent pin or drift.

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1 17-46
Camshaft Timing Chain
4 Loosen intake camshaft sprocket mounting nuts (arrows) by
1 turn.
Loosen exhaust camshaft sprocltet mounting bolts:
Release bolts
(A) 112 turn
Release nuts
(B) 2 turns
Pull out intake camshaft splined shaft out approx.
1 mm
(0.04 in) of splines (arrows) can be seen.