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- .. -.
-. Engine Removal and in=/
4 Remove left interior ventilation duct:
Release duct locking tabs (A). Early models: release
loclc
ing strap.
* Rotate duct inward (arrow) to detach.
Release spring
loclc (El) to unlock ventilation housing.
Disconnect electrical harness connector from hood switch
(C).
Release locking clip and remove ventilation filter cover (D).
Slide air housing away from inner fender to remove.
Removal
of right side ventilation duct is similar.
4 Remove rear engine compartment bulkhead panel:
Remove rubber sealing strip.
* Remove 3 mounting clips (A).
Remove harness supporting clip
(El).
Unlock panel retainers (arrows).
Lifl out panel.
< Separate engine wiring harness (arrow) from electrical box
at right side of engine compartment:
Remove E-box cover.
Disconnect electrical harness connectors leading from en-
gine wiring harness (arrow). Connectors are labelled (A,
El, C. D, E) for locating purposes.
Lay engine harness on top of engine.
- Drain engine coolant from engine block and radiator. See 170
Radiator and Cooling System.
Remove drain plugs from right and left side of engine
bloclc
(between cylinders 213 and 617).
Afler coolant has drained, reinstall drain plugs using new
sealing washers.
Drain radiator and reinstall drain plug.
Tightening
torques
Coolant drain plug to cylinder block (M14) 25 Nm (18 ft-ib)
Radiator drain screw to radiator 2.5
Nm (22 in-lb)
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Engine Removal and Installation
Tightening torques
ATF cooler lines to radiator
(use new O-rings)
MI8 cap nut 20 Nm (15 ft-lb)
M22 cap nut
22
Nm (17 ft-lb
Coolant drain plug to cylinder
blocic (M14) 25 Nm (18 ft-lb)
Engine mount to engine bracket or 47 Nm (35 ft-lb)
subframe (M10)
Exhaust flange nuts (8 mm) 25 Nm (18 ff-ib)
Radiator cooling fan to coolant pump 40 Nm (30 ft-lb)
(left-hand threads)
Radiator drain screw to radiator 2.5 Nm (22 in-lb)
Wirino to alternator
(ME nut) 13 Nm (9.5 ft-lb)
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11 3-3
Cylinder Head Removal and Installation
4 Rotary angle torque dial gauge
(Tool No. BMW
11 2 250100 9 120)
4 El2 Torx socket for cylinder head bolts
(Tool No.
BMW 11 2 250)
4 Crankshaft loclting tool
(Tool No.
BMW 11 2 300)
4 Camshaft locking tool set, 6-cylinder
/I (Tool No, BMW 11 3 240)
< Timing chain adjustable tension setup tool, 6-cylinder
(Tool No.
BMW 11 4 220)
>
Double VANOS adiustment date
4 Secondary sprocket setup tool for double VANOS
(Tool No. BMW
11 6 180)
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. .- . --
Lr -- - - - -- Cylinder Head Removal and Installation I -
- Release pressure at compression gauge valve, then remove
gauge from spark plug hole. Repeat test for each cylinder
and compare results with values given in Table a.
Table a. Compression testing specifications
Minimum compression
6-cylinder
10-1 1 bar (142-156 psi)
V-8 12-14 bar (174-203 psi)
Maximum difference between
cylinders (all engines)
0.5 bar (7 psi)
- Compression readings may be interpreted as follows:
Low compression indicates a poorly sealed combustion
chamber.
0 Relatively even pressures that are below specification nor-
mally indicate worn piston rings
andlor cylinder walls.
Erratic values tend to indicate valve leakage.
Dramatic differences between cylinders are often a sign of
a failed head
gasket, burned valve, or broken piston ring.
- If readings are within specifications, reinstall spark plugs and
ignition coils.
NOTE-
Used spark plugs should be reinstalled in the same cylinder
from which they were removed.
Tightening torque Spark plug to cylinder head 25 Nm
(18 ft-lb)
lanition coils to cylinder head 10 Nm (7.5 ft-lb)
- Remainder of installation is reverse of removal. Be sure to re-
install all wires disconnected during test, especially ground
wires at coils and cylinder head cover (where applicable).
Wet compression test
To further help analyze the source of poorcompression,awet
compression test is the next step.
- Repeat compression test, this time squirt a teaspoon of oil
into each cylinder. The oil will temporarily help seal between
piston rings and cylinder wall, practically eliminating leakage
past rings for a short time.
- If this test yields a higher reading than "dry" compression
test, there is probably leakage between piston rings and
cylinder walls, due either to wear or to broken piston rings.
- Little or no change in compression reading indicates other
leakage, probably from valves.
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I Cylinder Head Removal and Installation
4 Check that two locating dowels are correctly positioned in
block and are not damaged.
- Apply permanently elastic sealing compound Three Bond
1209 8 to joints where cylinder block joins timing case cover.
- Place new cylinder head gasket on cylinder block.
NOTE-
The word "OBEN" or 'TOP': printed on the gasket, should
face up. The cylinder head
gasket will fit correctly in only one
orientation.
- With camshafts locked in TDC oosition with BMW soecial
tools as described during cylinder head removal,
seicylinder
head in position, guiding primary chain through cylinder head
opening.
NOTE-
* The camshafts must be locl(ed in the TDC position at the
rear of the cylinder head with
BMW special tool I1 3 240
before installing the cylinder head.
Make sure the
cranksha% which had been rotated approx-
imately
30" opposite the direction of engine rotation, is still
in that position before lowering the cylinder head into posi-
tion.
- Lightly lubricate new cylinder head bolts. Loosely install bolts
and their washers, then thread them in until they are finger
tight.
NOTE-
. Torx-type cylinder head bolts should not be reused. They
are stretch-type bolts and must always be replaced when-
ever loosened.
Check that all washers for the cylinder head bolts are in
place before installing the bolts. Some of the washers may
be
stalced to the cylinder head.
CAUTIOI\C
Cylinder head bolts for a cast iron engine block are different
length and require different tightening torque than bolts for an
aluminum cylinder bloclc engines
(95 rnm versus 110 rnm
bolts).
- Install cylinder head-to-lower timing chain cover bolts finger
tight.
< Tighten cylinder head bolts in correct sequence to initial
torque value.
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I Cylinder Head Removal and Installation I
< Use BMW tool 11 2 110 or torque angle gauge to tighten cyl-
inder head bolts in sequence to stage
2 and 3.
Tightening torques
Cylinder head to cast iron
bloclc
Staoe 1
staie 2
Stage 3
Cyllnder head to aiumlnum block
Stage
1 40 Nm (30 it-lb)
Stage 2 +90°
Staoe 3 -80"
- Tighten cylinder head-to-lower timing chain cover bolts.
Tightening torques
cylinderhead to lower timing chain cover 10 Nm (89 in-lb)
- Inspect secondary chain guide rail and tensioner rail for
grooves caused by chain contact. Replace any part that is
worn.
NOTE-
Inspect timing chain sprocl(ets. Sprockets that have worn
or missing teeth should be replaced.
* If any of the sprockets are being replaced due to wear, the
chain should also be replaced.
If the crankshaft sproclet requir?s replacement, the oil
pump drive sprocket and chain must be removed as de-
scribed under
119 Lubrication System.
The procedure outlined below assumes that the camshafts
and the
cranl(shaft are locledin the TDCposition with special
4 Mount primary timing chain sprocltet to primary chain so that
arrow on sprocket faces up. Mount sprocket to camshaft so
that tapped holes in camshaft are on left side of elongated
holes in sprocltet
Install BMW special tool
1 I 4 220 into primary timing chain
tensioner sleeve. Thread center spindle in finger tight
until
slack is removed from chain.
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--
Cylinder Head Removal and Installation
NOTE-
BMW special tool 11 4 220 is an adjustable primary chain
tensioner and simulates the function of the hydraulic
tensioner.
- Check that elongated holes in primary sprocket are now cen-
tered to bolt holes in camshaft and chain is free of slack. If
not, reposition sprocket to chain and reinstall.
- lnstall secondary timing chain guide and secondary chain
tensioner. Tighten mounting bolts (tensioner remains locked
down for now using
BMW special tool 11 3 292).
- Install cylinder identification trigger plate to front of intake
camshaft with studs.
- Install spacer to front of intake camshaft.
- Install secondary chain sprockets and chain as an assembly
so that arrows on sprockets are pointing up. Center mounting
holes in sprockets to bolt holes in camshafts.
4 lnstall thrust washers and diaphragm spring to intake cam
sprocket.
I 2hm thrust washer I
- Install shim and torx bolts to exhaust camshaft. Tighten fin-
ger tight; do not torque down.
- Tighten intake sprocket nuts.
CA UTIOG
Hold the camshaft stationary (at hex on camshaft) when loos-
enino or tiahtenino sorocket mounting bolts and studs.
Tightening torque
Intake s~rocket nuts to studs 10 +l Nm (89 +9 in-lb)
- Turn crankshaft approx. 30" in direction of rotation to bring
engine to TDC. Lock crankshaft in TDC position with BMW
special tool
11 2 300.
CAUTION-
The camshafts andcranlshaft must be lockedin the TDCpo-
sition using BMW special tools 11 2 300 and 11 3 240. If the
camshafts and cranl(shaft are not at TDC, the valves can
contact the pistons.
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- -.
Cylinder Head Removal and lnstallation
NOTE-
Be Sure the secondary timing chain tensioner is locked down
and the exhaust
camshaif mounting bolts are loose before
proceeding.
- Install VANOS control unit. See VANOS control unit, install-
ing
(M52 engine) in 117 Camshaft Timing Chain.
CAUTION--
Incorrect installation ofthe VANOS control may result in dam-
age to the engine valvefrain.
- Install exhaust manifolds using new gaskets and nuts. Coat
manifold studs with copper paste prior to installing nuts.
Install intake camshaft cover and cylinder
head cover.
Check 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
(6) of half-moon cutouts.
Seat gasket and seal corners in front of cylinder head at
VANOS unit.
- Installation of remaining parts is reverse of removal, noting
the following:
Reinstall electrical harness connectors for oil pressure
switch and coolant temperature sensor before installing in-
take manifold.
Refill cooling system as described in 170 Radiator and
Cooling System.
Change engine oil and filter as described in 020 Mainte-
nance.
If necessary, adjust accelerator cable.
Reconnect battery last.
Tightening Torques
VANOS oil line
32 Nm (24
ft-lb)
VANOS solenoid to control unit 30 Nm (22 ft-lb)
Coolant drain plug to cylinder
block 25 Nm (18 ft-lb)
Cylinder head cover to cylinder head
10 Nrn (89 in-lb)
(M6 bolts)
intake manifold to cylinder head 15 Nm (I 1 ft-lb)
Radiator cooling fan to coolant pump
40 Nm (30 ft-lb) - . .
Radiator drain screw to radiator 2.5 Nm (22 in-lbl