1999 BMW 525i tow

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Cylinder Head Removal and installation - - .- - - - -
4 Disconnect electrical harness connections at exhaust cam-
shaft position sensor and exhaust camshaft VANOS control
valve (arrows).
4 Remove banjo bolt from VANOS unit oil pressure line. Use
banjo bolt to attach
BMW special tool 11 3 450 (compressed
air fitting) to VANOS control unit.
CAUTIOI\C
Oil will drain from pressure line. Have a drain container and
rags ready Do not allow oil to run onto drive belts.
4 Cover oil hole (arrow) in VANOS unit with shop towel to cap-
ture oil which will spray when compressed air is applied.
- Connect compressed air line to air fitting. Apply air pressure
set to
2-8 bar (30-1 15 psi).
4 With compressed air line connected, rotate engine at vibra-
tion damper in direction of rotation (clockwise) at least twice,
until cylinder 1 intake and exhaust camshaft lobes face each
other (arrows) in the top dead center (TDC) position for cyl-
inder
1.
CAUTION--
Do not rotate engine counterclocltwise to reach the top dead
center position. If engine rotated beyond top dead center;
complete another two complete rotations.

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- -
-- .- Cylinder ~ead~ernoval and Installation I - -.
Remove VANOS unit:
Remove engine lifting eye.
- Remove VANOS mounting nuts (arrows) and pull VANOS
unit and metal gasket off.
CAUTION-
Do not crank the engine with VANOS unit removed. Pis-
tonhalve inteiference may result.
NOTE-
The VANOS unit will contain a small quantity of oil. Place
shop towel to catch oil as unit is removed or tilted.
CAUTION-
If the VANOS adjustment unit is replaced, or if operations are
completed that may change the timing of
the camshafts, the
camshaft timing must be checked. See
11 7Camshaft Timing
Chain.
4 Remove primary camshaft chain tensioner cylinder (arrow).
CAUTION-
Primary camshaft chain tensioner is under spring pressure.
Press down on secondary chain tensionerand lock into place
using
BMW special tool 11 3 291, or a thin drifl or pin.

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. - -- -
Cylinder Head Removal and Installation --
Remove bolts (arrows) holding timing chain cover to cylinder
head. (Photo shows camshafts and camshaft bearing caps in
place).
4 Using BMW special tool 11 2 250 or equivalent, loosen cylin-
der head bolts in several stages, in sequence shown. Discard
head bolts.
NOJE-
BMW special tool 11 2 250 is a thin-walled Torx El2 socket
with an extended reach. The cylinder head bolts are re-
cessed into the head below the
camshaft towers with little
working space.
- Lift off cylinder head. Refer to 116 Cylinder Head and Val-
vetrain for cylinder head reconditioning information.
Cylinder head, installing, M52 TU and M54
engines
Clean cylinder head and gasket surfaces of cylinder bloclc
and all timing chain covers.
CAUTION- Remove foreign matter and liquid from bolt holes. Trapped oil
or coolant in bolt holes can cause damage to
blocl~,
CAUJION-
Do not use a metal scraper or wire brush to clean the alumi-
num cylinder head or pistons. If necessary, use a hard wood-
en orplastic scraper. Also available are abrasive discs to be
used in conjunction with an electric drill. Be sure to use the
correct disc for the type of metal being cleaned.
Evaluate cylinder head as shown in
116 Cylinder Head and
Valvetrain.
NOTE- If the cylinder head has been machined, a special 0.3
mm
(0.01 1 in.) thicker gasket should be installed. The thicker
gasket is available from an authorized
BMW dealer and
should be marked accordingly
Cylinder head and valve specifications are covered in 116
Cylinder Head and Valvetrain.

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Camshaft Timing Chain -- - -1
Q Remove oil baffle cover
from intake
camshaft
Remove front engine lifting bracket fasteners (arrows
A) and
remove bracket.
- Remove cable duct clips (arrows B) from front of VANOS
control unit.
Rotate engine
clocltwise and set camshafts to Top Dead
Center (TDC). Cylinder
1 camshaft lobes will point towards
each other (arrows).
4 Remove plug from below starter and install crankshaft lock-
ing tool
(BMW special tool 11 2 300).

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Camshaft Timing chain1
Using a drift, drive two locating dowels (arrows) in lower
timing cover toward rear of car.
4 Remove timing cover mounting bolts (arrows).
* Carefully slide cover with water pump forward to remove
CAUTION-
Use care when removing the cover from the cylinder head
gasket If the cover is stuck, use a sharp knife to separate
it from the head gasket.
If cylinder head gasket is damaged, remove cylinder
head and replace head
gaslet. See 113 Cylinder
head and valvetrain.
- Remove timing cover locating dowels by driving them
forward.
- Lift primary chain sprocket off crankshaft sprocket and
remove chain.

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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 Remove VANOS unit:
Remove fasteners from engine support eye.
Remove VANOS mounting nuts (arrows) from cylinder
head. Slide VANOS control unit and metal gasltet off.
NOJE-
The VANOS control unit will contain residual oil. Place
shop towels beneath adjustment unit when removing.
If the VANOS control unit is replaced, or if repair operations
are completed that may change camshaft timing, the cam-
shaft timing must be checked as described in VANOS tim-
ing,
checlcing and adjusting (M52 JU and M54
engines).
CAUJION-
Do not crank the engine with VANOS unit removed.
Piston/valve interference may result.
VANOS control unit, installing
(M52 TU and M54 engines)
< Clean contact edges of cylinder head face and double
VANOS control unit and apply a thin coat of sealing com-
pound (Three Bond
1209 8 or equivalent) to surfaces.
I CAUJION-
. Make sure all gaskel material is removed from lace of
cyl~nder head. Clean sealing lace and keep lree of oil.
Checklocating dowel (A) and dowelsleeve (B) at top of
cylinder head for damage or incorrect installation.
NO
JE -
If the Double VANOS control unit is beino reolaced. be -.
sure to check and adjust camshaft timing, see VA NOS
timing, checking and adjusting (M52 JU and M54 en-
gines).
* If work being carried out has no effect on camshaft timing,
it is not necessary to recheck the timing. It is recommend-
ed, however, that the VANOS operation be checked using
a compatible scan tool once the engine is running.

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-
I Lubrication System - I
Oil pressure, checking
The oil pressure warning switch is located at the base of the
oil filter housing.
In 6-cylinder engines access to oil pressure warning switch
connector (arrow) is extremely restricted (intake manifold re.
moved for the purpose of illustration).
V-8 engine oil pressure warning switch (arrow) is at base of
oil filter housing on left engine compartment inner fender.
Oil pressure is tested by removing oil pressure switch and in-
stalling oil pressure gauge in its place.
Unscrew oil filter cap in order to allow engine oil to drain back
down into oil pan.
Disconnect harness connector from oil pressure switch and
remove switch.
NOJE-
Thoroughly clean around the oil pressure switch before
removing it.
Be prepared to catch leaking oil with a shop towel.
- Install pressure gauge in place of oil pressure switch,
- With gauge installed, start engine and allow to reach operat-
ing temperature. Check oil pressure. See Table b.
NOJE-
For the most accurate test results, the engine oil and filter
should be new. The oil should be the correct grade.
Table b. Engine oil pressure
At idle 0.5 bar (7 psi)
At elevated speed
6-cylinder engine 4.0 bar
(59 psi)
V-8 engine 4.5 bar (66 psi)