Correct answer
By initially closing the main radiator circuit while allowing internal flow.
It initially keeps the main radiator circuit closed while coolant can circulate through the internal bypass. This limits heat loss through the radiator during warm-up; at the specified temperature it opens that circuit to dissipate heat. It does not mean stopping all circulation or manually blocking pipes. Do not rev a cold engine highly to warm it; follow manufacturer instructions.
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By stopping all coolant circulation in the engine.
By requiring the driver always to rev the engine highly.
By initially closing the main radiator circuit while allowing internal flow.
The real exam in English is a translation of the Spanish original; compare both here.
Show the Spanish original
En un circuito convencional de refrigeración líquida con termostato y derivación interna, ¿cómo favorece el termostato el calentamiento de un motor frío?
- Deteniendo toda circulación de refrigerante en el motor.
- Obligando al conductor a acelerar siempre a régimen elevado.
- Manteniendo cerrado inicialmente el circuito principal al radiador y permitiendo el flujo interno.(Correct answer)
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