Engineering · Cooling — Thermostat
A diesel engine cooling-water thermostat that sticks closed will cause:
- AOvercooling and white smoke
- BOverheating, because coolant flow to the cooler is blocked✓ Correct
- CLoss of lube oil pressure
- DLow fuel pressure
Explanation
A stuck-closed thermostat blocks coolant flow to the heat exchanger, so heat is not rejected and the engine overheats. A stuck-open thermostat causes overcooling and slow warm-up, hurting efficiency and combustion.
Authority: Modern Marine Engineer's Manual; cooling systems
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