ac low pressure switch BMW 528i 2000 E39 Workshop Manual

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113-10
Cylinder Head Removal and Installation
4 Working above engine, disconnect the following:
Vent line from cylinder head cover
(A).
. Oxygen sensor connectors (B).
Electrical harness connector from VANOS solenoid
valve
(C).
Electrical harness connectors at throttle valve position
switch
(D), ASC valve position switch (E), fuel injector har-
ness
(F) and vent valve (G).
CAUTION-
Be sure to mark oxygen sensor harness connectors so that
they can be reassembled correctly Do not interchange con-
nectors.
4 Where applicable, remove schraeder valve cap (arrow) from
air connection on fuel rail. Using a tire chuck, blow fuel back
through feed line using a brief burst of compressed air (max-
imum of
3 bar or 43.5 psi).
WARNING-
. Fuel in fuel line is underpressure (approx. 3 - 5 bar or 45 -
75 psi) and may be expelled. Do not smoke or work near
heaters or other fire hazards. Keep a fire extinguisher
handy Before disconnecting fuel hoses, wrap a cloth
around fuel hoses to absorb any leaking fuel. Catch and
dispose of escaped fuel. Plug open fuel lines.
- Always unscrew the fuel rank cap ro release pressure
;n the tank before working on the tank or lines.
Disconnect fuel lines by sliding locking collar in (arrows) and
pulling lines apart.
NOTE-
BMW uses three styles of fuel line connections; a one-time
use
clamp; a locking fitting that uses BMWspecial tool 16 1
050 to release; and a quick release sleeve (above) that dis-
connects the line when depressed.

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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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11 9 Lubrication System
General ............................ 11 9-2
Special tools
......................... 11 9-2
..................... Engine lubrication 11 9-3
Troubleshooting .................... 11 9-3
................. Oil pressure. checking 11 9-4
...... Oil pressure warning system. testing 11 9-5
Crankshaft Rear Main Seal ......... .I1 9-6
Crankshaft rear main seal.
replacing (6-cylinder)
.................. 11 9-6
Crankshaft rear main seal. replacing (V-8)
. . 11 9-8
Engine Oil Pan .................... .I1 9-10
Oil pan. removing and
................. installing (6-cylinder) .I1 9-10
Lower oil pan. removing and
installing (V-8)
....................... 1 19-1 3
Upper oil pan. removing and
installing (V-8)
....................... 11 9-1 5
.......... Component Replacement 11 9-20
Oil pressure warning switch. replacing
.................. (6-cylinder and V-8) 11 9-20
Oil level warning switch. replacing
.................. (6-cylinder and V-8) 11 9-21
Oil pump. removing and
................. installing (6-cylinder) 11 9-22
Oil pump. removing and installing (V-8)
. . 11 9-24
..... Oil pressure relief valve (6-cylinder) 119-26
.......... Oil pressure
relief valve (V-8) 11 9-27

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1 19-3
Lubrication System
V-8 crankshaft rear main seal tool
(Tool No. BMW
11 1 230)
I i 4 V-8 crankshaft rear main seal ouide
4 Adapter for BMW oil pressure gauge
(Tool No. BMW
11 4 050)
Engine lubrication
Oil pressure is generated by a gear-type pump bolted to the
bottom oi the engine block. The oil pump is chain driven off
the front of the crankshaft.
Table a. Engine oil capacity (includes oil filter replacement)
6-cylinder 6.5
liters (6.9
US qt)
V-8 7.5 liters (7.9 US qt)
The oil pressure warning system consists of an oil pressure
switch mounted in the oil circuit and an instrument
panel
warning light. Other saiety features include:
Q A filter bypass to provide lubrication should the oil filter be-
come clogged.
An oil pump pressure relief valve to prevent excessive sys-
tem pressure.
CAUTIOI\C
If the red oil pressure warning light comes on or flashes on
while driving, always assume that the oilpressure is low. Stop
the engine immediately and make arrangements to test oil
pressure.

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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)

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. .- -
L
- --
- - -. - -- Lubrication ~~stern
- Remove pressure gauge and reinstall pressure switch with
new sealing washer.
Tightening torque
Oil pressure switch to oil filter housing 27 Nm (20 ft-lb)
If testing shows low oil pressure, one or more of the following
conditions may be indicated:
Worn or faulty oil pump or faulty pump pressure relief valve
Worn or damaged engine bearings
Severe engine wear
Any of these conditions indicate the need for major repairs.
Oil pressure warning system, testing
4 When the ignition is turned on, the oil pressure warning light
comes on. When the engine is started and the oil pressure
rises slightly, the oil pressure switch (arrow) contact opens
and the warning light goes out. Make sure the oil level is cor-
rect before making tests.
- Turn ignition switch on.
- Warning light on instrument panel must light up
- Remove connector from oil pressure switch.
Warning light on instrument panel must go out.
NOTE-
If the light does not go out, the wiring to the switch is most
likely grounded somewhere between the switch terminaland
the warning light See
ELE Electrical Wiring Diagrams for
electrical schematics.
- If warning light does not light when ignition is on, remove con-
nector from oil pressure switch and use a jumper wire to
ground connector terminal to a clean metal surface. The oil
pressure warning light should come on.
NOTE-
If there are two wires to the oil pressure switch, ground the
brown/green wire that carries the signal to the warning light.
- If the warning light comes on, check the switch as described
in the next step. If the warning light does not come on, the
wiring to the instrument cluster or to the light itself is faulty.

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Lubrication System
To test switch, connect an ohmmeter between terminal in
switch body (arrow) and ground. With engine off, there
should be continuity. With engine running, oil pressure
should open switch and there should be no continuity. Re-
place a faulty switch.
CAUTION-
Keep in mind that low oil pressure may be preventing the
switch from turning the light out
If the light remains on while
the engine is running, check the oil pressure as described
earlier. Do not drive the car until the problem is corrected. The
engine may be severely damaged.
Crankshaft rear main seal replacement requires removal of
the transmission and flywheel.
Crankshaft rear main seal, replacing
(&cylinder)
- Remove transmission. See 230 Manual Transmission or
240 Automatic Transmission.
- Manual transmission vehicles: Remove clutch pressure plate
and disc. See
210 Clutch.
- Remove flywheel. See 210 Clutch or 240 Automatic Trans-
mission.
- Drain engine oil.
4 Remove seal carrier bolts from oil pan (arrows). Loosen all
oil pan bolts.

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Lubr~cat~on System r- -
Working at lower rear of engine, remove oil pan retaining
bolts
(arrows).
- If necessary, remove oil cooler bracket from oil pan.
- Remove remaining oil pan bolts. Slide upper section of oil
pan forward to remove.
- Installation is reverse of removal, noting the following:
Clean sealing surfaces of debris.
- Coat joints with Three Bond 1209 O sealant.
Use new gaskets.
Install all oil pan bolts first, installing bolts at transmission
end without preload.
Tighten oil pan bolts at front end, then tighten bolts at rear
of engine.
Be sure to reinstall all oil
pump fasteners, including the
sprocl - After adding engine oil, start and run engine. Raise engine
speed to
2,500 rpm until oil pressure warning light goes out
(about
5 seconds).
Tightening torques
AIC drive belt tensloner
M6 10 Nm (7.5 it-lb)
M8 24 Nm (18 ft-lb)
Front axle
subframe to chassis
(Use new fasteners) 77 Nm (57 ft-lb)
Oil drain
line to upper oil pan 30 Nm (22 ft-lb)
Oil pump to crankcase 34 Nm (25 ft-lb)
Oil pan fasteners
(upperllower)
M6 8.8 10 Nm (7.5 ft-lb)
M6 10.9 (replace)
I2 Nm (9 ft-lb)
M8 8.8 22 Nm (16 ft-lb)
Steering column universal joint to
steering box (replace) 19 Nm (14 ft-lb)
Oil pressure warning switch, replacing
(&cylinder and V-8)
- In all models, the oil pressure warning switch is located at the
base of the oil filter housing.

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Fuel Injection 1
NOTE-
The 1998 5281' with MS 41.1 requires a barometric pressure
sensor input signal for activation of the
LDP check. This sen-
sor is located on the passenger side strut tower
fo~lard of
ABS/ASC hydraulic unit.
Evaporative emissions
1. ECM
2. Purge valve
3. Leak detection pump (LDP) (in
lefl rear wheel housing)
4. Filter
5. Liquid vapor separator
6. Purge canister
7. Fuel tank
Secondary air injection, overview
The secondary air system pumps ambient air into the exhaust
stream afler a cold engine start to reduce the warm up time of
the catalytic converters and to reduces HC and CO emis-
sions. The ECM controls and monitors the secondary air in-
jection system. The secondary air pump operates at a start
temperature of between 10°C (50°F) and 40°C (104°F) and
continues to operate for a maximum of
2 minutes at idle
speed.
The electric air pump draws in ambient air and supplies it to
the divertervalve. The vacuum ventvalve (solenoid) switches
vacuum to open the divertervalve when activated by the
ECM. Once opened, the diverter valve allows air to be
pumped into the exhaust stream.

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130-43
Fuel Injection ]
I I I
12 llnput IFeedback signal, engine start /Starter
Table c. Siemens MS 42.0 and MS 43.0 ECM pin assignments (continued)
I I - I
13 Input /I Alternator (generator) Notes
Throttle
valve
Crankshaft position sensor
Throttle valve (MS
42.0)
Throttle valve
Pin
6
7
8
9
10
11
14
15
16
17
18
19
20
I 1- I
23 l~round I~round, intaite air temperature sensor /Intake air temperature sensor
Signal
Output
Input
Input
Input
I I I
Component/function
Not used
Throttle valve supply potentiometer
2
Signal, crankshaft position sensor
Signal,
pedal position sensor 2 (MS 42.0)
Signal, throttle position sensor 1
Not used
Ground
Ground
Input
Ground
Ground
Input
Ground Cranltshaft position sensor
21
24
25
26
27
28
29
30
I 1- I
33 1 input ISignal, cylinder 1 fuel injector /cylinder 1 fuel injector
Ground, throttle position sensor (MS
42.0)
Ground, exhaust camshaftsensor I
Signal, pedal position sensor 1 (MS 42.0)
Ground, mass air flow sensor
Ground, intake camshaft sensor
1
Signal, throttle potentiometer 1
Ground, throttle position sensor
22 loutput I~ignal, intake air temperature Ilntake air temperature sensor
I I - I
Throttle
valve (MS 42.0)
Camshaft position sensor I
Throttle valve (MS
42.0)
Hot film mass air flow sensor
Camshaft position sensor i
Throttle valve
Throttle valve
Ground
Output
Ground Input
Output
Ground
Output
Out~ut
Ground, crankshaft position sensor
Knoclt sensor
31
34
35
36
37
38
39
Signal, coolant temperature sensor
Ground, coolant temperature sensor
Signal,
oil pressure
Signal, engine
oil temperature sensor
Ground, engine oil temperature sensor
Signal, knock sensor
Signal, knock sensor
32 loutput ISignal, ltnock sensor l~nock sensor
40
41
Coolant temperature sensor
Coolant temperature sensor
Oil pressure switch
Oil temperature sensor
Oil temperature sensor
Knoclt sensor
I Output
Input
input
Input
Input
Input
Inout
Signal, knock sensor
Input
Input Signal, cylinder
2 fuel injector
Signal, cylinder
3 fuel injector
Signal, cylinder
4 fuel injector
Signal, cylinder
5 fuel injector
Signal, cylinder
6 fuel injector
Sianai, oil level sensor Cylinder
2 fuel
injector
Cylinder
3 fuel injector
Cylinder
4 fuel injector
Cylinder
5 fuel injector
Cylinder
6 fuel injector
Oil level sensor
-
Signal. VANOS inlet valve
Signal. VANOS outlet valve VANOS
inlet valve
VANOS outlet valve