Examkin

Question

Difficulty: MediumCooling System

An automotive engine has reached its normal operating temperature. In what sequential order does coolant circulate through the closed cooling system to absorb and dissipate engine heat?

  1. 1The water pump pressurizes and forces coolant into the engine block water jackets.
  2. 2Coolant absorbs heat as it rises from the block into passages surrounding the cylinder head and combustion chambers.
  3. 3Heated coolant flows past the open thermostat and travels through the upper radiator hose.
  4. 4Coolant passes through the radiator core tubes while airflow across the cooling fins removes heat.
  5. 5Cooled fluid exits the bottom of the radiator via the lower hose and returns to the water pump suction inlet.

Answer

Water pump forces coolant into engine block -> Coolant rises to cylinder head -> Flows past open thermostat into upper radiator hose -> Passes through radiator core to dissipate heat -> Returns through lower radiator hose to water pump inlet.
In a liquid cooling system at operating temperature, the water pump pushes coolant into the engine block jackets, where it absorbs heat and rises into the cylinder head. Hot coolant exits past the open thermostat into the upper radiator hose, travels through the radiator core where fins transfer heat to passing air, and returns via the lower radiator hose to the water pump suction inlet.

Step-by-Step Solution

1
Identify the starting point of mechanical fluid movement in the cooling system.
The water pump draws in cooled fluid and pumps it into the engine block water jackets.
The water pump acts as the primary mechanical circulation device for the entire system.
2
Trace the internal flow path through the engine.
Fluid absorbs heat from the cylinders and rises into the cylinder head passages.
Coolant absorbs heat progressively, moving from lower cylinder walls to the high-heat combustion chambers in the head.
3
Follow the path out of the engine at normal operating temperature.
Coolant flows past the open thermostat into the upper radiator hose.
The thermostat opens once operating temperature is reached to permit coolant discharge toward the radiator.
4
Trace the thermal dissipation stage through the heat exchanger.
Coolant travels through the radiator core tubes as airflow carries away thermal energy.
The radiator provides large surface area through tubes and fins to transfer heat to the outside air.
5
Complete the closed-loop cycle back to the pump.
Cooled liquid exits the radiator through the lower hose and enters the water pump inlet.
The lower hose routes low-temperature coolant back to the pump to begin circulation again.

Key Concept

Coolant circulation path through an internal combustion engine cooling loop at operating temperature
Estimated Time:1m 0s
Rate this question

Topics

Cooling System

More questions from this topic