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Diesel Engine revision module 4 of 8

COOL

Cooling and Overheating

Raw water, fresh water, impellers, strainers, seacocks, alarms, and overheating response.

raw-water coolingimpeller

4 guided lessons · 8 practice questions · 8 flashcards

3 outcomes · self-guided revision
  • Explain raw water, fresh water, impellers, strainers, seacocks, alarms, and overheating response.
  • Apply raw-water cooling to a realistic onboard situation.
  • Recall the core check: raw water enters through a seacock and strainer.

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Lesson routeCooling System Types0/1 read

Lesson 1 of 1

Cooling System Types

Marine diesels usually remove heat with raw seawater, a closed freshwater coolant circuit, or a heat exchanger using both. Many installations also inject seawater into the exhaust to cool the exhaust gases and hose.

The operator needs to know the layout on their own engine: seacock, strainer, raw-water pump, impeller, heat exchanger or engine waterways, thermostat, coolant tank, exhaust injection point, and alarms.

  • Raw water enters through a seacock and strainer.
  • Impellers move seawater in many systems.
  • Closed systems need coolant level and antifreeze checks.
  • Exhaust water flow is a critical early check on many boats.
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