Examkin

Soru

Zorluk: OrtaCooling System

A vehicle's engine rapidly overheats shortly after starting, but an inspection reveals that the upper radiator hose remains cold to the touch while the engine block is boiling hot. Which of the following components is most likely stuck closed and preventing coolant from reaching the radiator?

  1. A
    Water pump bypass valve
  2. B
    Radiator pressure cap
  3. ThermostatCevap
  4. D
    Heater control valve

Cevap

The thermostat is the component stuck closed.
The thermostat regulates engine operating temperature by remaining closed during warmup and opening once the coolant reaches a predetermined temperature (typically between 180∘F180^{\circ}\text{F} and 195∘F195^{\circ}\text{F}). When the thermostat sticks closed, hot coolant cannot leave the engine block to enter the radiator via the upper hose. As a result, the engine quickly overheats while the upper radiator hose remains noticeably cold.

Adım Adım Çözüm

1
Analyze the observed symptoms and coolant flow path.
The engine block is overheating, but the upper radiator hose connecting the engine outlet to the radiator remains cool.
Hot coolant must exit the cylinder head/engine block through the thermostat housing and upper hose to be cooled by the radiator.
2
Identify the temperature-sensitive valve located at the engine coolant outlet.
The thermostat controls the flow of coolant from the engine to the radiator based on operating temperature.
When stuck shut, the thermostat completely blocks hot coolant from passing into the upper hose and radiator core.

Anahtar Kavram

Thermostat Thermal Regulation and Flow Control
Tahmini Süre:1m 0s
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Konular

Cooling System

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