02:01-01

Issue 3 en
Industrial & Marine Engines

Cooling system - Industrial engines

Function description

Part No.
1 588 419 © Scania CV AB, Sweden 1999-10:3
 Contents
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Coolant circuit, 9-series engines . . . . . . . . . . . . . . . . . . . . . . . . . 4
Coolant circuit, 11-series engine . . . . . . . . . . . . . . . . . . . . . . . . . 5
Coolant circuit, 12-series engine . . . . . . . . . . . . . . . . . . . . . . . . . 6
Coolant circuit, 14-series engine . . . . . . . . . . . . . . . . . . . . . . . . . 7
Coolant circuit, 16-series engine . . . . . . . . . . . . . . . . . . . . . . . . . 8
Radiator and expansion tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Coolant pump, 9-series engines. . . . . . . . . . . . . . . . . . . . . . . . . 11
Coolant pump, 11-series engines. . . . . . . . . . . . . . . . . . . . . . . . 12
Coolant pump, 12-series engines. . . . . . . . . . . . . . . . . . . . . . . . 13
Coolant pump, 14-series engines. . . . . . . . . . . . . . . . . . . . . . . . 14
Coolant pump, 16-series engines. . . . . . . . . . . . . . . . . . . . . . . . 15
Thermostat and thermostat housing. . . . . . . . . . . . . . . . . . . . . . 16
Radiator fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Level indicator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Charge air cooler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

2 © Scania CV AB, Sweden 1999-10:3 02:01-01

 General

The cooling system maintains the operating - Oil cooler for engine lubrication oil.
temperature of the engine at a suitable level. This
is extremely important for the operating cost and - Coolant pump.
service life of the engine. - Thermostat housing with thermostat and
Cooling system assemblies used in Scania bypass channel.
industrial engines have sufficient capacity to work • Engine external cooling system: (non-
at atmospheric pressure, thus increasing the standard)
reliability of the system.
- Radiator and expansion tank.
Scania cooling systems are not equipped with
pressure caps as standard for 9-, 12- and 14-series - Temperature gauge and level indicator.
engines.
- Radiator fan
16-series engines with Scania cooling system are
equipped with pressure caps as standard, which - Lines (pipes and hoses).
ensures extra safety at high outputs and in warm
- External heat sources (e.g. cab heater)
climates.
connected to the cooling system.
- Engine heater
A cooling system assembly for an industrial
engine consists of:
• Engine internal cooling system: (standard)
- Coolant passages in the cylinder block and 1
cylinder head.
8 9 10

6 3

1. Expansion tank 5. Coolant pump 9. Ventilation lines

2. Radiator 6. Thermostat housing 10. Level indicator
3. Static line 7. Radiator fan
4. Drain tap 8. Fan ring
Scania cooling systems for industrial engines

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 Coolant circuit, 9-series engines

The coolant pump and the oil cooler are combined On a DI engine the coolant exits the oil cooler
in one unit, located on the right hand side of the connection housing directly after the oil cooler. It
engine. is then directed to the charge air cooler, where it
From the oil cooler the coolant flows to a flows backwards in the lower part and then
distributor passage in the engine block and then forwards in the upper part before returning to the
upwards, and flows around the cylinder liners and pump suction side via the bypass line, where it is
through each cylinder head to an external water mixed with coolant from the radiator.
manifold on the left-hand side of the engine.
The front part of the water manifold is connected
to the thermostat housing.

1 2 3 4

11

13

12

11
10 9 8 7 6 5

1. Fan 7. Outlet line from charge air 10. Static line

2. Bypass line cooler 11. Ventilation line
3. Coolant pump 8. Inlet line to charge air 12. Radiator
4. Oil cooler (full flow) cooler 13. Expansion tank
5. Charge air cooler 9. Thermostat housing with
thermostat
6. Water manifold

Coolant circuit, 9-series engines (DI9 A)

4 © Scania CV AB, Sweden 1999-10:3 02:01-01

 Coolant circuit, 11-series engine

From the pump, the coolant is directed to the From the rear cylinder head the coolant flows
longitudinal cylinder block distributor passage forwards to the front cylinder head and exits the
and then through openings in the cylinder block, it engine directly into the thermostat housing, which
then flows around the cylinder liners and then is located on the right-hand side of the front
upwards to the cylinder heads. cylinder head.
The coolant is pumped directly up into the On DI engines the coolant exits the cylinder block
cylinder heads from the distributor passage via directly after the coolant pump and is directed to
passages directed towards injectors and exhaust the charge air cooler, where it flows backwards in
valves. the upper part and then forwards before exiting
through the lower connection. It then returns in a
pipe between the oil cooler and the pump suction
side where it is mixed with coolant from the
radiator.

1 2 3 1 4 5

12

11

10 9 8 7 6

1. Ventilation line 6. Charge air cooler 10. Coolant pump

2. Static line 7. Outlet line from charge air 11. Fan
3. Expansion tank cooler 12. Radiator
4. Bypass line 8. Inlet line to charge air
5. Thermostat housing with cooler
thermostat 9. Oil cooler (full flow)

Coolant circuit, 11-series engines (DI11 A)

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 Coolant circuit, 12-series engine

From the coolant pump, the coolant is directed to From the cylinder head the coolant flows forwards
the longitudinal cylinder block distributor in a water manifold and exits the engine directly
passage, where it first goes through the oil cooler into the thermostat housing, which is located on
and then through openings in the cylinder block, the right-hand side of the front cylinder head.
then flows around the cylinder liners and then On DI engines the coolant exits the cylinder block
upwards to the cylinder heads. directly after the coolant pump and is directed to
The coolant is pumped directly up into the the charge air cooler, where it flows backwards in
cylinder heads from the distributor passage via the lower part and then forwards before exiting
passages directed towards injectors and exhaust through the upper connection. The coolant from
valves. the charge air cooler then returns in a pipe
connected to the connection housing on the pump
suction side where it is mixed with coolant from
the radiator.

3
1
1 2 4 5 9

12

11 10 8 7 6

1. Ventilation line 6. Charge air cooler 10. Coolant pump

2. Static line 7. Outlet line from charge air 11. Fan
3. Expansion tank cooler 12. Radiator
4. Bypass line 8. Inlet line to charge air
5. Thermostat housing with cooler
thermostat (double) 9. Oil cooler (full flow)

Coolant circuit, 12-series engines (DI12 A)

6 © Scania CV AB, Sweden 1999-10:3 02:01-01

 Coolant circuit, 14-series engine

The coolant pump pumps the coolant into the From the cylinder heads the coolant is directed
cylinder block distributor passages through into two water manifolds towards the centre of the
passages in the timing gear casing. engine and forwards into a passage in the timing
From the distributor passages the coolant is gear casing. It then exits the engine via the
pumped further into the cylinder block, flows thermostat housing at the front end of the timing
around the cylinder liners and then upwards to the gear casing on the right-hand side.
cylinder heads. On a DI engine the coolant exits the cylinder
The direction of flow of the coolant in the cylinder block front side directly after the coolant pump
head is regulated so that the exhaust valve is and is directed to the charge air coolers. There it
sufficiently cooled. flows backwards in the lower part and then
forwards in the upper part before returning in a
common pipe to the bypass channel in the timing
gear housing, where it is mixed with coolant from
the engine before the thermostat housing.

2 1 3 4 5
1

12

11

10

8 7 6

1. Ventilation line 5. Coolant pump 9. Fan

2. Expansion tank 6. Charge air cooler 10. Bypass line
3. Static line 7. Oil cooler 11. Thermostat housing with
4. Inlet line to charge air 8. Outlet line from charge air thermostat
cooler cooler 12. Radiator

Coolant circuit, 14-series engines (DI14 A)

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 Coolant circuit, 16-series engine

The coolant from the radiator is directed into the The coolant from the cylinder heads is collected
front, lower right-hand side part of the cylinder on both sides in manifolds in the outer part of the
block and through a passage into the coolant cylinder block.
pump. The coolant in the two manifolds flows forwards
The coolant pump then pumps the coolant into the in the cylinder block to a passage in the front end
upper centre part of the cylinder block past the oil of the cylinder block that leads the coolant on to
cooler and to the distributor passages. the thermostat housing.
From the distributor passages the coolant is If the thermostats are closed, the coolant is
pumped further into the cylinder block, flows transported back to the pump suction side via a
around the cylinder liners and then upwards to the bypass channel in the front end of the cylinder
cylinder heads. block.
The direction of flow of the coolant in the cylinder
head is regulated so that the exhaust valves are
sufficiently cooled.

2 3 1 8
1

5
9

7 4

1. Ventilation line 5. Oil cooler 8. Thermostat housing with

2. Expansion tank 6. Fan thermostat (double)
3. Static line 7. Bypass line 9. Radiator
4. Coolant pump
Coolant circuit, 16-series engines (DC16 A)

8 © Scania CV AB, Sweden 1999-10:3 02:01-01

 Radiator and expansion tank

8 1
9-, 12- and 14-series engines: 7
2
The radiator consists of two vertically mounted
radiator tanks and a cooling package that connects
them.
The cooling package consists of horizontal thin-
walled brass pipes in three rows for 1.0 and 1.2
m2 radiators and two rows for 0.75 m2 radiators.
1.0 and 1.2 m2 radiators: The pipes pass through
thin copper plate discs to maximise the radiator
thermal dissipation.
0.75 m2 radiators: Thin copper plates are located
within the pipe row matrix to maximise the 6
radiator thermal dissipation.
One of the radiator tanks (radiator inlet) is
connected to the outlet on the engine thermostat
housing.
The other radiator tank (radiator outlet) is
connected to the coolant pump suction side, like 5 4 3
the bypass line.
The expansion tank is made of plastic and is 1. Expansion tank
located above the radiator. It has a filler pipe with 2. Cooling package
cap and an integrated float level monitor. 3. Drain tap
The filler cap in a standard expansion tank does 4. Outlet from radiator
not contain a delivery and vacuum valve. This cap 5. Inlet to radiator
must not be replaced with a cap with a delivery 6. Radiator tank
valve. 7. Venting
The expansion tank also has a direct connection, 8. Filler cap
static line, to the coolant pump suction side. This
line reduces the vacuum in the pump inlet and 9-, 12- and 14-series engines:
thus the risk of cavitation in the pump. Radiator and expansion tank
When the thermostat(s) open(s) the coolant is
transported to the lower side of the radiator and
then flows horizontally through the radiator where
it is cooled by the air stream generated by the fan
(if it is a vehicle, the ram air) passing through the
radiator.

02:01-01 © Scania CV AB, Sweden 1999-10:3 9

16-series engine:
The 0.8 m2 radiator consists of two vertically
mounted radiator tanks and a cooling package that
connects them.
The cooling package consists of horizontal thin-
walled aluminium pipes in three rows. Thin
aluminium plates are located within the pipe row
matrix to maximise the radiator thermal
dissipation.
One of the radiator tanks (radiator inlet) is
connected to the outlet on the engine thermostat
housing.
The other radiator tank is connected to the coolant
pump suction side.
The expansion tank is made of plastic and is
located above the radiator. It has a filler pipe with
pressure cap.
When the thermostats open, the coolant is
transported to the upper right-hand side of the
radiator and then flows horizontally through the
radiator where it is cooled. It returns to the engine
from the lower left-hand side of the radiator.
The 1.3 m2 radiator consists of two radiator
tanks positioned at the top and bottom and a
cooling package that connects them.
The cooling package consists of vertical thin-
walled aluminium pipes in three rows. Thin
aluminium plates are located within the pipe row
matrix to maximise the radiator thermal
dissipation.
The plastic expansion tank is integral with the
radiator and is located on top of it.
It has a filler pipe with pressure cap and level
monitor, venting and static line integration.
When the thermostats open, the coolant is
transported to the upper part of the radiator and
then flows vertically through the radiator where it
is cooled. It returns to the engine from the lower
part of the radiator.

10 © Scania CV AB, Sweden 1999-10:3 02:01-01

 Coolant pump, 9-series engines

The coolant pump and the oil cooler are combined

in one unit, located on the right hand side of the
engine.
The coolant pump is driven directly by the
crankshaft damper via a poly-V-belt.
It is a centrifugal-type pump and consists of a
spiral-shaped pump housing with an impeller
located directly on the half shaft. The shaft is
carried in the housing by two ball bearings that are
permanently lubricated.
The pump shaft bearing is sealed with a flexible
axial seal to prevent coolant entering.

1 2 3 4

8 7 6 5

1. Coolant enters the engine 5. Coolant pump

2. Cool oil 6. Coolant from radiator
3. Oil to be cooled 7. Oil cooler
4. Coolant from thermostat housing 8. Connection housing with connection
(alternative inlet from radiator, 6 is point for engine heater and feed to
then plugged) charge air cooler

Coolant circulation through coolant pump and oil cooler, 9-series engine

02:01-01 © Scania CV AB, Sweden 1999-10:3 11

 Coolant pump, 11-series engines

The coolant pump is located in front of the engine

and is driven from the crankshaft pulley by the
V-belts.
It is a centrifugal-type pump and consists of a
spiral-shaped pump housing with an impeller
located directly on the half shaft. The shaft is
carried in the housing by two ball bearings that are
permanently lubricated.
The pump shaft bearing is sealed with a flexible
axial seal to prevent coolant entering.

1 2

1. Outlet to engine
2. Bypass channel
3. Coolant from radiator and oil
cooler and return from
charge air cooler

Coolant circulation through coolant pump, 11-series engine

12 © Scania CV AB, Sweden 1999-10:3 02:01-01

 Coolant pump, 12-series engines

The coolant pump is located in front of the front

engine cover on the right-hand side of the engine.
The coolant pump is driven directly by the
crankshaft damper via a poly-V-belt.
It is a centrifugal-type pump and consists of a
spiral-shaped pump housing with an impeller
located directly on the half shaft. The shaft is
carried in the housing by two ball bearings that are
permanently lubricated.
The pump shaft bearing is sealed with a flexible
axial seal to prevent coolant entering.

3
4
2

1. Outlet to engine
2. Bypass channel
3. Static line
4. Return line from charge air
cooler 5

1
Coolant circulation through coolant pump, 12-series engine

02:01-01 © Scania CV AB, Sweden 1999-10:3 13

 Coolant pump, 14-series engines

The coolant pump is mounted on the engine

timing gear casing. It is driven via the camshaft
gear.
It is a centrifugal-type pump and consists of a
spiral-shaped pump housing with an impeller
located directly on the half shaft. The shaft is
carried by two ball bearings that are lubricated by
oil spray from the timing gear housing.
The pump shaft bearing is sealed with a flexible
axial seal to prevent coolant entering.

4
5

3 2

1. Outlet to engine
2. Coolant from radiator and oil
cooler
3. Outlet to engine
4. Bypass channel
5. Static line connection

Coolant circulation through coolant pump, 14-series engine

14 © Scania CV AB, Sweden 1999-10:3 02:01-01

 Coolant pump, 16-series engines

The coolant pump is located on the front right-

hand part of the cylinder block.
The coolant pump is driven directly by the
crankshaft pulley via a poly-V-belt.
It is a centrifugal-type pump and consists of a
spiral-shaped pump housing with an impeller
located directly on the half shaft. The shaft is
carried in the housing by two ball bearings that are
permanently lubricated.
The pump shaft bearing is sealed with a flexible
axial seal to prevent coolant entering.

1. Coolant from radiator or bypass channel

enters the coolant pump
2. Coolant from pump enters the cylinder block

02:01-01 © Scania CV AB, Sweden 1999-10:3 15

 Thermostat and thermostat housing

11- and 14-series industrial engines have two If the coolant temperature in the engine is higher
thermostats while 9-series engines only have one than the temperature for a fully open thermostat,
thermostat. the bypass channel is closed and all fluid flows
12- and 16-series engines have a double through the thermostats and to the radiator.
thermostat. When temperature equilibrium is reached within
When two thermostats or a double thermostat are the thermostat control range, i.e. between the
used they are set to the same standard opening temperature limits for fully closed and fully open
temperature. thermostat, the thermostat valves shift to the
corresponding intermediate position. A part of the
The thermostats use wax as the temperature coolant then is directed to the fluid pump without
sensing medium. being cooled, and the rest is directed to the
At coolant temperatures below the thermostat radiator.
opening temperature, all coolant circulates
between the engine cooling passages and the
coolant pump without passing through the
radiator.

A B
1. Outlet to radiator
2. Coolant from engine
3. Bypass channel
A = closed thermostat - return to coolant pump through bypass channel
B = open thermostat - full flow to the radiator
Thermostat housing with thermostat, 9-series engine

16 © Scania CV AB, Sweden 1999-10:3 02:01-01

 3

1 1

A B

1. Coolant from engine

2. Bypass channel (return to
coolant pump)
3. Outlet to radiator

A = closed thermostat - return to coolant pump through bypass channel

B = open thermostat - full flow to the radiator
Thermostat housing with thermostats, 11-series engine

02:01-01 © Scania CV AB, Sweden 1999-10:3 17

 1

2
A
1. Coolant from engine
2. Bypass channel (return to
coolant pump)
3. Outlet to radiator

A = closed thermostat - return to coolant pump through bypass channel

B = open thermostat - full flow to the radiator
Thermostat housing with thermostats, 12-series engine

1
B

18 © Scania CV AB, Sweden 1999-10:3 02:01-01

 3

1
1

A B

1. Coolant from engine

2. Bypass channel
3. Outlet to radiator
A = closed thermostat - return to coolant pump through bypass channel
B = open thermostat - full flow to the radiator
Thermostat housing with thermostats, 14-series engine

02:01-01 © Scania CV AB, Sweden 1999-10:3 19

 A B

1. Outlet to radiator
2. Coolant from engine
3. Bypass channel
A = closed thermostat - return to coolant pump through bypass channel
B = open thermostat - full flow to the radiator
Thermostat housing with thermostat, 16-series engine

20 © Scania CV AB, Sweden 1999-10:3 02:01-01

 Radiator fan

The engines are available with either a suction or With a pushing fan the air is heated, 3° - 5°
pushing radiator fan. There are four different depending on engine type and installation, when it
standard sizes. passes the engine before the radiator. This also
With a suction fan better air distribution across the has a negative impact on the cooling capacity.
radiator is achieved if there is only a short To improve the fan efficiency, it has an airtight
distance between fan and radiator (100-150 mm). fan ring. A fan cover is positioned between the
The improved air distribution gives a more radiator and fan ring to direct all air to the fan
efficient cooling than with a pushing fan. through the radiator.
The cooling capacity with a pushing fan can be The cooling capacity is influenced by the size of
improved somewhat by increasing the distance the radiator, the fan diameter and fan speed, and it
between fan and radiator. is reduced if there is any risk of recirculation. The
size of the fan and the fan speed also affect the
power requirement and the noise level.

Air flow through radiator with pushing fan Air flow through radiator with suction fan

02:01-01 © Scania CV AB, Sweden 1999-10:3 21

Level indicator 3
1
The level indicator warns when the coolant level
is too low.
9-, 12- and 14-series engines:
When the engine is equipped with a Scania
cooling system the level indicator has two
terminals and is located in the expansion tank.
The indicator consists of a magnetic float (1),
mounted in a housing in the expansion tank, a
level monitor (2) fitted in the float housing and a
warning lamp in the instrument panel. 2

1. Float
2. Level sensor
3. Expansion tank

9-, 12- and 14-series engines:

Level indicator in Scania cooling system
16-series engine:
All-speed engines with 0.8 m2 radiator: The level
monitor has 2 terminals and is located in the static
line from the expansion tank.
Single speed engines with 1.3 m2 radiator: The
level monitor, of the same type as for the 0.8 m2
radiator, is located in the expansion tank which is
integrated in the radiator.

16-series engine:
Level indicator in static line

22 © Scania CV AB, Sweden 1999-10:3 02:01-01

 Charge air cooler

Charge air cooling is available as an option on Cold air has a higher density and contains more
supercharged engines. oxygen by volume than heated air. The
Two principles of operation are used: (see the type temperature of the intake air increases when
designation) passing through the turbocharger. If the air then is
cooled in a charge air cooler, the density increases
• DI:water to air and more oxygen is supplied to the engine. This
• DC:air to air means that more fuel can be burnt.
Maximum engine output depends among other As a result, a higher engine output and torque can
things on the amount of air and fuel that can be be achieved. The cooled air lowers the combustion
supplied to the engine. temperature as well as the temperature of the parts
affected by the combustion, resulting in lower
thermal stress in spite of the increased engine
output.

DI engines - water to air

The coolant circuits for the various DI engines are described on pages 4, 5, 6 and 7.

DC engines - air to air

The DC engines have pipes that lead air from after When it has been cooled, the intake air flows back
the turbocharger to the charge air cooler, which is to the intake manifold, which distributes the air to
either located between the engine and the radiator the cylinders.
or in front of the radiator (see figure).

1. Charge air cooler

2. Radiator
3. Intake air pipe
4. Exhaust

Air distribution in a DC engine (16-series engine shown)

02:01-01 © Scania CV AB, Sweden 1999-10:3 23