low oil pressure BMW 525i 2001 E39 Workshop Manual

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General
WARNING-
Never run the engine in tile work area unless it is well-ven-
tilated. The exhaust should be vented to the outside. Car-
bon monoxide (CO) in exhaust kills.
Remove all neckties,
scarfs, loose clothing, or jewelry
when working near a running engine or power tools.
Tuck in shirts. Tie long hair and secure it under a cap.
Severe injury can result from these things being
caugiit
in rotating parts.
Remove rings, watches, and bracelets. Aside from the
dangers of moving parts, metallic jewelry conducts
electricity and may cause shorts, sparks, burns, or
damage to the electricalsystem when accidentally con-
tacting the battery or other electrical terminals.
Disconnect the battery negative
(-) cable whenever
working on or near the fuel system or anything that is
electrically powered. Accidental electrical contact may
damage the electrical system or cause a fire.
Fuelis highly flammable. When working around fuel, do
not
smoke or work near heaters or other fire hazards.
Keep an approved fire extinguisher handy.
The fuel system is designed to retain pressure even
when the ignition is off When worlcing with the
fuelsys-
tem, loosen the fuel lines slowly to allow the residual
pressure to dissipate gradually. Take precautions to
avoid spraying fuel.
. Illuminate the worlc area adequately and safely Use a
portable safety light for worlcing inside or under the car.
A fluorescent type
light is best because it gives off less
heat. If using a light with a normal incandescent bulb,
use rough service bulbs to avoid
breakage. The hot fil-
ament of an accidentally broken bulb can ignite spilled
fuel or oil.
Keep sparks, lighted matches, and any open flame
away from the top of the battery. Hydrogen gas
emitted
by the battery is highly flammable. Any nearby source
of ignition may cause the battery to explode.
Never lay
tools or parts in the engine compartment or
on top of the battery. They may
fallinto confinedspaces
and be difficult to retrieve, become caught in belts or
other rotating parts when the engine is started, or
cause electrical shorts and damage to the electrical
system.

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020-1 4
Maintenance
- When oil flow has diminished to an occasional drip, reinstall
drain plug with a new metal sealing washer and torque plug.
Tightening torque Engine oil drain plug to oil pan
25 Nrn (1.8 ft-lb)
6-cylinder oil filter assembly
r------ 1
< Working at oil filter housing (1):
Lubricate and install new oil filter O-rings (3, 4).
Install a new filter cartridge (5).
lnstall and tighten housing cover (2).
6-cylinder oil filter assembly shown, V-8 is similar.
Tightening torque Cover to oil filter housing
25 Nm (1.8 it-lb)
- Refill crankcase with oil. Approximate oil capacity is listed in
Tabled. Engine oil with filter change. Use dipstick to
check correct oil level.
- Start engine and check that oil pressure warning light
immediately goes out.
- Allow engine to run fora few minutes to circulate new oil, then
check for leaks at drain plug and oil filter. Stop engine and re-
check oil level
The section describes other routine maintenance done in the
engine compartment. Information on engine oil service is
giv-
enkar~ier inthis group.
For these procedures, it is not necessary for the car to be
raised and supported off the ground.
Accelerator and linkage
The accelerator and linkage at the throttle housing should be
lubricated periodically. Use ageneral purposeoil on the joints
and bearings of the linkage. Use a multipurpose grease on
the bearing points of the throttle plate.
Air filter, replacing
The specified replacement intervals forthe air filter are based
on normal use. If the car is operated primarily in dusty
conditions, the air filter should be serviced more frequently.

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Maintenance
Suspension, front, inspecting
Inspection of the front suspension and steering includes a
check of all moving parts
forwear and excessive play. Inspect
ball joint and tie-rod rubber seals and boots for cracks
ortears
that could allow the entry of dirt, water, and other
contaminants. See
310 Front Suspension.
Suspension, rear, inspecting
Differential and rear drive axle service consists of checking
and changing the gear oil, inspecting for leaks, and checking
the drive axle
CV joint boots for damage.
The areas where
lealts are most likely to occurare around the
drive shaft and drive axle mounting flanges. For more infor-
mation on identifying oil leaks and theircauses, see
330 Rear
Suspension and
331 Final Drive.
Tires, checking inflation pressure
Correct tire pressures are important to handling and stability,
fuel economy, and tire wear. Tire pressures change with tem-
perature. Pressures should be
checked oRen during season-
al temperature changes. Correct inflation pressures can be
found on the driver's door pillar and in the owner's manual.
Note that tire pressures should be higher when the car is
more heavily loaded.
WARNING-
Do not inflate any tire to a pressure higher than the tire's max-
imum inflation pressure listedon the sidewall. Use care when
adding air to warm tires. Warm tire pressures can increase as
much as
4 psi (0.3 bar) over their coldpressures.
Tires, rotating
BMW does not recommend tire rotation. Due to the car's sus-
pension design, the front tires begin to wear first at the outer
shoulder and the reartires begin to wearfirst at the middle of
the tread or inner shoulder. Rotating the tires may adversely
affect road handling and tire grip.
Transmission service, automatic
The automatic transmissions installed in E39 models are
filled with special automatic transmission fluid. The transmis-
sion lubricant type can be found on the "type-plate" on the
side of the transmission. The recommended lubricants are
listed earlier in this repair group. See Fluids and lubricants.
If in doubt, consult an authorized BMW dealer for alternate

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I Engine Removal and Installation
WARNING -
Use extreme caution when draining and disposing of engine
coolant. Coolant is poisonous andlethal to humans andpets.
Pets are attracted to coolant because of its sweet smell and
taste. Seek medical attention immediately if coolant is ingest-
---
Working at rear of intake manifold:
Disconnect brake booster vacuum line (A).
Disconnect fuel tank vent line
(6).
Disconnect hoses (C and D) at coolant manifold
- Remove transmission harness support (E).
- Remove oil filter housing assembly from fender:
- Remove oil filter housing mounting fasteners.
Use stiff wire to secure oil filter housing to engine.
NOTE-
Do not disconnect oil lines from filter housing.
4 Disconnect supply and return fuel lines (where applicable) at
or near fuel rail. Plug open fuel lines.
NOTE-
BMW uses three styles of fuel line connections; a slngle use
clamp, a locking fitting that uses special tool
16 7 050 to re-
lease, and a
quiclc release sleeve (arrows) that disconnects
the line when depressed.
WARNING-
Fuel In fuel line is under pressure (approx. 3 - 5 bar or45 -
75 psi) and may be expelled. Do not smoke or worlc near
heaters or other fire hazards. Keep a fire extinguisher
handy. Before disconnecting fuel hoses, wrap a cloth
around fuel hoses to absorb any lealcing fuel. Catch and
dispose of escaped fuel. Plug all open fuel lines.
. Always unscrew the fuel tank cap to release pressure
in the tank before worlcing on the tank or lines.
< Remove air filter housing and mass air flow sensor:
Disconnect mass air flow sensor (A) and
intalte air temper-
ature sensor
(6) electrical harness connectors.
. Remove air filter housing mounting fastener (arrow).
Loosen intake hose clamp (C).
M62 engine: Remove hose at idle air stabilizer.
Remove air filter housing with mass air flow sensor.
Remove intalte hose from throttle body.

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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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- -.
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

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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 Head Removal and Installation
- Install exhaust manifolds using new gaskets and nuts. Coat
manifold studs with copper paste prior to installing nuts.
Tightening torque Exhaust
maniiold to cylinder head (M7)
20 Nm (15 ft-lb)
- Install electrical harness connectors for oil pressure sender
and coolant temperature sensor before installing
intalte man-
ifold.
7 Install intake manifold:
1. Manifold mounting nuts: tighten to 15 Nm (1 1 ft-lb)
2. Fuel pipe bracltet
3. Fuel pipe bracltet
4. Vacuum pump bracltet
5. Manifold mounting bracltet
6.
Tank venting valve bracltet
7. Mounting bracket to manifold bolt (M6)
8. Mounting bracket to cylinder block nut (MIO), tighten to
47 Nm (33 fi-lb)
Intake manifold installation is reverse of removal, noting the
following:
* Use new fuel injector seals.
Carefully
check intake manifold gasket and replace if nec-
essary.
Inspect O-ring seal between mass air flow sensor and air
filter housing. To facilitate reassembly, coat seal with
acid-
free grease.
Use new fuel injector seals.
Carefully check intake manifold gasket and replace if
necessary.
CA UTIOPI-
When reattaching throttle assembly harness connector, con-
nector is fully tightened when arrows on connector
andplug
line up.
Tightening torque
lntalte manifold to cylinder
head (M7)
15 Nm (1 1 it-lb) ~ ~- Mounting bracket to cylinder bloclt (M10) 47 Nm (33 ft-lb)
Mounting bracket to intake manifold (MI?) 10 Nm (89 in-lb)

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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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Table d. Valve guide specifications
Specifications
All engines (1997-2002)
Valve guide wear, maximum 0.5 mrn (0.020 in)
(valve tilt clearance
measured
with new valve)
Valve guide inside diameter,
installed
(tolerance per IS0 allowance H7)
Standard 6.0 mm (0.236 in)
Oversize
1 6.1 mrn (0.240 in)
Oversize 2 6.2
mm (0.244 in)
Valve stem oil seals
The purpose of the valve stem oil seal is to prevent excess oil
from entering the combustion chamber. The sign of faulty
valve stem oil seals is excessive oil consumption and smoke
from the exhaust immediately after starting and during decel-
eration.
NOTE-
Valve stem oil seals should not be reused. If valves are re-
moved, new valve stem oil seals should be installed.
Valve stem oil seal replacement requires that the cylinder
head be disassembled and the valves removed as described
above under Valves, removing and installing.
NOTE-
BMW special tools are available to remove the valve stem oil
seals. As an alternative, standard valve seal removal tools
are available from most automotive parts stores.
Lubricate new seal and install using hand pressure only. Be
sure to install valve spring
seat(s) before installing seal.