2003 BMW 745i air condition

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N62B44 Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Objectives of the Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Purpose of the System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Technical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Engine Views . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Components
Fresh Air System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
- Air Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
- Throttle Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
- Intake Manifold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
- Crankcase Venting System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Exhaust System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
- Exhaust Manifold with Catalytic Converter . . . . . . . . . . . . . . . . . . . . . . . 13
- Silencers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
- Secondary Air System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Ancillary Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
- Belt Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
- Alternator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
- Air Conditioning Compressor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
- Starter Motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
- Power Steering Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Cylinder Heads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
- Engine Covers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
- Valve Gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
- Valvetronic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
- Bi-VANOS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
- Vacuum Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
- Chain Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Downloaded from www.Manualslib.com manuals search engine Throttle Valve
The throttle valve on the N62 is not necessary for engine load control. This is carried out
by the intake valves variable lift adjustment.
The tasks of the throttle valve are:
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Airflow is controlled by the throttle valve during the starting procedure when the air temp-
erature is between 20 ºC and 60 ºC, .
If the engine is at operating temperature, it will be switched to non-throttle mode approx-
imately 60 seconds after start up. In cold conditions however, the engine is started with
the throttle valve fully opened because this has a positive effect on the starting characteris-
tics.
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This vacuum is needed to exhaust the blow-by gases from the crankcase and the fuel
vapors from the activated charcoal filter.
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If the Valvetronic system should fail, the throttle valve implements conventional load con-
trol).
7
N62 Engine
42-02-25
Throttle Valve
• Throttle Valve Housing with Throttle Valve.
• Throttle Valve Actuator
• Two Throttle Valve Potentiometers

Downloaded from www.Manualslib.com manuals search engine Secondary Air Pump (SLP)
The electrically-operated secondary air pump is mounted to the vehicle body. The pump
draws out filtered fresh air from the air cleaner housing during the warm-up phase and sup-
plies it to the two secondary air Non-return Valves.
Once the engine has been started, the secondary air pump is supplied with voltage by the
ECM via the secondary air pump relay. It remains switched on until the engine has taken in
a certain amount of air.
The O ON
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period may be a maximum of 90 seconds and it depends on the following engine
operating conditions:
• Coolant temperature (from -10 ºC to approximately 60 ºC)
• Air temperature (NTC sensor in HFM)
• Engine speed
One non-return valve is mounted on each cylinder head (see also Engine Views).
The non-return valves are opened by the pressure generated from the secondary air pump.
The secondary air is led through a pipe to the secondary air ducts (integral in the cylinder
heads) for distribution into the exhaust ports.
The non-return valves are sprung closed when the secondary air pump is deactivated. This
prevents exhaust vapors, pressure and condensation from flowing back into the secondary
air pump.
15
N62 Engine
43-02-14
View From Rear of The Cylinder Head
1. Cylinder Head Lead
2. Non-return Valve (SLV)
3. Secondary Air Pump Connection

Downloaded from www.Manualslib.com manuals search engine Ancillary Components and Drive Belts
Drive Belts
The belt drive has two components and is subdivided into the main and A/C drives. Both
belts are driven by the crankshaft pulley.
A 4 rib belt is used to drive the air conditioning compressor and a 6 rib belt is used for the
main drive. Each drive belt has a maintenance free tensioning unit with tensioning pulley
and torsioner.
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The tensioning pulley is pushed back using a
Torx tool in the recess provided (1) and fixed in
this position by inserting a locking pin as shown
(2).
16
N62 Engine
42-02-15 Ancillary Components and
Drive Belts
1. Air Conditioning Compressor
2. 4 Rib A/C Drive Belt
3. Crankshaft Pulley
4. Water Pump
5. Tensioning Unit Main Drive Belt
6. Alternator
7. Deflection Pulley
8. Power Steering Pump
9. 6 Rib Drive Belt
10. Tensioner Unit A/C Drive Belt
42-02-16

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The alternator regulator voltage is influenced by the ECM - BSD interface. The bat-
tery charge voltage can therefore be up to 15.5 V, depending on the battery temperature.
If a battery charge voltage of up to 15.5 V is measured, the regulator is not faulty. A high
charge voltage indicates a low battery temperature.
Air Conditioning Compressor
The “clutch free” A/C compressor is manufac-
tured by Denso. It functions continuously with
the engine running. The compressor is a 7-
cylinder swash plate type. The displacement
can be reduced to less than 3% when air con-
ditioning is not requested (no refrigerant is sup-
plied to the refrigerant circuit).
There is an internal compressor refrigerant cir-
cuit to maintain lubrication. The IHKA electron-
ics regulate the compressor output via an
external control valve (1).
Starter Motor
The starter motor is located on the right-hand
side of the engine below the exhaust manifold,
and is a compact planetary drive starter with a
1.8 kW output.
1. Starter motor with heat protective cover.
Power Steering Pump
The power steering pump is a tandem radial piston pump on vehicles equipped with
Dynamic Drive. A single vane pump is installed on vehicles without the Dynamic Drive.
Further information about the power steering pump can be found in the Chassis Dynamics
section.
19
N62 Engine
42-02-19
42-02-03

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N62 Engine
Map-controlled Thermostat
The map-controlled thermostat allows the engine to be cooled relevant to operating con-
ditions. This reduces fuel consumption by approximately 1-6%. The electrical connections,
the design and the map-controlled thermostat response have been enhanced. The map-
controlled thermostat function is the same as previous engines (M62).
Cooling Module
The cooling module contains the following main cooling system components:
• Cooling radiator
• Air conditioning condenser
• Transmission oil/water heat exchanger
• Hydraulic fluid radiator
• Engine oil radiator
• Main electric fan
• Fan shroud for viscous coupling fan
All the components (with the exception of the transmission oil radiator) can be removed for
repairs without disassembling any other coolant circuit. All connections have been fitted
with the quick-release coupling which are used in current models.
Maped-Controlled Thermostat
1. Radiator Return Flow To Thermostat
2. Connection for Thermostat Heating Element
3. Temperature Sensor
4. Radiator in-flow (hot coolant from engine)