Seawater System - Volvo Penta TAMD74A-A Operator's Manual

Maintenance: Freshwater system

Seawater system

The seawater system is the engine's external cooling system. The seawater pump draws in water via the seawa-
ter intake and pump it on through the charge air cooler, heat exchanger and the reverse gear oil cooler. The sys-
tem is protected against galvanic corrosion by zinc anodes located in the charge air cooler, heat exchanger and
the reverse gear oil cooler.
WARNING! There is a risk that water will enter while working on the seawater system (if the boat is in the
water). Water may flow into the boat if a hose, plug or similar object located below the waterline. So always
close the seawater cock. If the boat does not have a seawater cock, the flow of water must be stopped in a
safe manner. The boat must be brought up on land if this is not possible.
S S S
46
S S
Seawater system. Drain
The seawater system must be drained during cold
weather when there is a risk of freezing to prevent the
system from bursting.
An alternative to draining is to keep the engine room
free from frost using an approved heater fan.
WARNING! Risk of water entering. Close the
seawater cock before starting work on the sea-
water system.
1. Close the seawater cock.
2. Remove the cover on the seawater pump and al-
low the water to run out.
3. Remove one drain plug (S) at a time and allow the
water to run out until all drain points on the engine
have been dismantled.
IMPORTANT! Make sure the coolant really
runs out. It may be necessary to clean away
deposits inside the drain cocks.
4. Drain the water from the reverse gear oil cooler by
opening tap (1).
5. Drain/empty any extra equipment such as the sea
water filter, bilge/flushing pump etc.
6. Install the cover on the sea water pump, connect
all hoses and close/install all drain taps and plugs
before you leave the boat.