Installation guide
1
2
9
8
10
10
11
3
4
5
7
6
1
2
3
4
5
7
6
Sea water filter cover
The transparent cover fits all seawater filters 
for D4 and D6 engines. 
Part no
21400685
Seawater filter 32 mm
The seawater filter should be installed in the 
cooling system’s suction line above the water 
line. The filter effectively separates any impuri-
ties from the seawater and contributes to ex-
tending the service life of the engine. The filter 
element is easy to clean.
Material: Plastic container and filter 
Connection: In: 32 mm, Out: 32 mm 
Height: 210 mm incl. hose connectors 
Width: 130 mm
Depth: 130 mm 
Rec. rubber hose: 1140664 (32 mm)
Part no
3583840
Seawater filter, heavy duty 63 mm
The filter has a large capacity suitable for use in 
extremely dirty or muddy waters. The filter ele-
ment is easily cleaned and is covered with a 
transparent cover for ease of inspection.
Material: Bronze casting with clear sight glass
Volume: Approx 5 liters
Hose connection: Hose int. dia 63 mm 
Rec. rubber hose: Part no. 1140671 
The kit contains: Filter, mounting brackets 
Part no Description
21298782 Seawater filter
21298806 Hose connection
961673 Hose clamp
COOlING sysTeM
The cooling system is an extremely important part of the  
engine assembly. A correct working temperature contributes 
to a longer operational lifespan of the engine and improved 
fuel economy. It is also important from a safety aspect. With 
a correctly dimensioned and correctly installed cooling sys-
tem, overheating of the engine, unnecessary stoppages and 
expensive repairs due to engine failure, can be avoided.
COOLING SYSTEMS CAN BE 
OF TWO DIFFERENT TYPES:
Sea water cooled (direct cooling), where sea water is directly pumped 
into the engine’s cooling system and subsequently discharged via the 
exhaust system (wet exhaust systems) or via a separate discharge 
point for cooling water (for dry exhaust systems).
Fresh water cooled (indirect cooling) where the engine has its own 
closed loop cooling system similar to that of a motor car. The tempera-
ture of the engine coolant is reduced by being passed through a heat 
exchanger which is itself cooled by a supply of continuously pumped 
sea water. The sea water is discharged either via the exhaust, when 
used with a wet exhaust system, or via a separate outlet, when used 
with a dry exhaust system.
Freshwater cooling has a number of advantages compared to sea  
water cooling, these being:
-  Better comfort, i.e. availability of domestic hot water and onboard 
heating. More extensive usage.
-  The anti-freeze and anti-corrosion agents contained within the  
coolant permit all year running. Should it be required to totally de-
commission the engine, the coolant channels can simply be filled with 
inhibitors.
- Reduced engine wear as a result of higher running temperatures.
- Extended engine life due to better corrosion protection.
It is a relatively simple operation to fit a fresh water cooling system to a 
sea water cooled engine.
SEA WATER COOLING 
1. Exhaust bend, wet type 
2. Engine cooling galleries 
3. Vacuum valve 
4. Sea water pump 
5. Sea water filter 
6. Cooling water intake 
7. Hose
FRESH WATER COOLING
1. Exhaust bend, wet type 
2. Engine cooling galleries 
3. Vacuum valve 
4. Sea water pump 
5. Sea water filter 
6. Cooling water intake 
7. Hose 
8. Heat exchanger 
9. Expansion tank 
10. Hot water outlet 
11. Hot water heater
Seawater filter, heavy duty 50 mm
The filter has a large capacity suitable for use in  
extremely dirty or muddy waters. The filter ele-
ment is easily cleaned and is covered with a 
transparent cover for ease of inspection.
Material: Plastic container and filter
Hose connection: Hose int. dia 50 mm
Height: 255 mm
Width: 220 mm
Depth: 200 mm
Volume: Approx. 2,7 litres 
Rec. rubber hose: Part no. 1140670 
Part no
21655254
Vacuum valve
For vessels with an engine installation at or below the water line a 
vacuum valve should be installed. The valve prevents siphonage occur-
ring through the seawater intake, resulting in water ingress to the engine.
Part no Hose dia.
21662701 16 mm
21662702 19 mm
21662703 22 mm
21662704 25 mm
Hose adapters
For connection of seawater filter to cooling hoses of other diameters, cut adapter if necessary. 
Hose clamps for connection to filter included. Hose clamps for cooling hoses have to be ordered 
separately. One or two adapters are required for an installation.
Part no Inner dia. Outer dia. Length
21951974 50 mm 32/38 mm 142/99 mm
21951975 32 mm 16/19 mm 87/62 mm
46 ENGINE ACCESSORIES – COOLING SYSTEM 47ENGINE ACCESSORIES – COOLING SYSTEM










