Suzki Burgman AN400. Manual - part 46

6-2     COOLING AND LUBRICATION SYSTEM

COOLING SYSTEM

DESCRIPTION

The engine is cooled by the forced circulation of engine coolant, using a high-capacity, centrifugal water
pump, through water jackets formed in the cylinder and cylinder head, and through the radiator. The
tube-and-fin type radiator is made of aluminum, which is characterized by lightness in weight and good heat
dissipation.
A wax-pellet type thermostat is used to regulate the flow of engine coolant through the radiator. As the cool-
ant temperature rises to about 82 °C (180 °F) the thermostat valve unseats and a normal coolant flow is
established. At about 95 °C (203 °F) the thermostat becomes completely open and, as a result, heat is
released to the atmosphere through the radiator core.

COOLING CIRCUIT

BY-PASS

RH

CRANKCASE

CYLINDER

HEAD

CYLINDER

WATER PUMP

COOLANT

TEMPERATURE

SENSOR

COOLING

FAN THERMO

SWITCH

RADIATOR

RESERVOIR

TANK

BREATHER

THERMOSTAT

COOLING AND LUBRICATION SYSTEM     6-3

ENGINE COOLANT

At the time of manufacture, the cooling system is filled with a
50:50 of pure water and coolant. This 50:50 mixture will provide
excellent heat protection, and will protect cooling system from
freezing at temperature above –30 °C (–22 °F).
If the motorcycle is to be exposed to temperature below –30 °C
(–22 °F), this mixture ratio should be increased up to 55 % or 60
%.

!

DRAINING ENGINE COOLANT

• Remove the side leg shield. (

"

7-15)

• Place under the water hose a container large enough for

receiving coolant.

• Remove the radiator cap.

!

• Disconnect the radiator hose 

 

1

 to let coolant drain off.

• Remove the hose 

 

2

 and drain coolant remaining inside the

engine.

* Coolant used should be of a high quality ethyleneg-

lycol base mixed with distilled water.

* Do not use an alcohol base coolant.
* The mixture ratio should not be higher than 60% and

lower than 50%.

* Do not use sealing additives in cooling solution.

Density (%)

Density (%)

20

40

60 80 100

20

10

0

30

40 50 60

0

-10

-20

-30

-40

-50

-60

-70

32

14

-4

-22

-40

-58

-76

-94

F

reezing point

Boiling point

Gauge pressure

1.5

0.9

0.5

0

FIG.1 Engine coolant density-freezing point curve.

FIG.2 Engine coolant density-boiling point curve.

302

284

266

248

230

212

150

140

130

120

110

100

Do not remove the radiator cap when the radiator is
hot.

6-4     COOLING AND LUBRICATION SYSTEM

REMOVAL AND DISASSEMBLY

RADIATOR

• Remove the front box. (

"

7-14)

• Drain the engine coolant. (

"

6-3)

• Disconnect the radiator inlet hose 

 

1

 and radiator cap hose

 

2

.

• Disconnect the cooling fan coupler 

 

3

.

• Remove the radiator 

 

4

.

• Disconnect the cooling fan thermo-switch coupler 

 

5

.

• Remove the cooling fan 

 

6

.

COOLING AND LUBRICATION SYSTEM     6-5

INSPECTION

RADIATOR

• Check the radiator for dirt or small bug stuck between the fins.
• Use compressed air for cleaning. If dirt is excessive, wash

with water.

• Fins bent or dented can be straightened using a small plane

screwdriver.

WATER HOSE

• If a crack or deformation is found with the water hose, replace

it with a new one. Check for leaks from the joint and if found,
retighten the clamp.

COOLING FAN

• Remove the front box. (

"

7-14)

• Disconnect the cooling fan coupler 

 

1

.

• Disconnect the cooling fan thermo-switch coupler 

 

2

 and

short-circuit it with a jumper wire.

• Connect an ammeter as shown in the right diagram and mea-

sure load current.

NOTE:
Removing the cooling fan from the motorcycle is not necessary
in the above test.

#

09900-25008: Multi-circuit tester set

$

Load current: 5 A maximum

• If current is out of specification or the fan does not turn,

replace the fan with a new one.

Fan motor

Ammeter

Battery