Cooling System; Raw Water System; Closed Cooling System (F-Series) - Volvo 5.0OSiE-J Operator's Manual

Cooling System

If a situation should occur where the cooling system is unable to provide adequate cooling, be sure to check three
possible causes before continuing to operate the engine:
•
Drive water intakes blocked. Tilt the drive up and look for obstructions to the water intakes (e.g., seaweed,
plastic bags, etc.).
•
Raw water pump impeller damaged or blocked. For additional information, see Impeller: Checking & Replac-
ing on page 83.
•
Faulty engine thermostat. For additional information, see Replacing the Engine Thermostat on page 78.
VPA 7748131 English 09-2007
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Raw Water System

Various Volvo Penta engines have a thermostat-con-
trolled raw water cooling system.
1. Cool water is drawn in through raw water intake
(A) by an impeller (C) connected to the raw water
pump (D) mounted on the front of the engine.
2. Water is pumped to the engine and routed by cir-
culating water through the cooling system (B).
3. A thermostat inside the engine determines the
amount of water to be taken in, recirculated, and
discharged to control the engine's operating tem-
peratures.

Closed Cooling System (F-Series)

Various Volvo Penta engines have a thermostat-con-
trolled, fresh water cooling system.
1. Cool water is drawn in through raw water intake
(E) by an impeller (F) connected to the raw water
pump (G) mounted on the front of the engine.
2. Water is pumped (H) to the heat exchanger (I),
which cools the engine cooling fluid (J). The raw
water is then routed to the exhaust manifolds
where it is mixed with exhaust and dumped over-
board through the sterndrive exhaust port.
3. The engine cooling fluid is recirculated between
the engine and the heat exchanger by the engine
circulation pump (K).
4. A thermostat inside the engine determines the
amount of water to be taken in and circulated to
the heat exchanger, then discharged to control
the engine's operating temperatures.
Maintenance
77