ESENRU

Topic: Vehicle mechanics and maintenance · Nº 318 / 539

Question picture

¿Es conveniente hacer una revisión exhaustiva del estado del vehículo si el humo que despide el tubo de escape es de color negro?

Is it advisable to have the vehicle thoroughly checked if the smoke coming out of the exhaust pipe is black?

  • ASí, porque el motor puede estar quemando aceite.Yes, because the engine may be burning oil.
  • BNo, porque solo es un problema de refrigeración que suele desaparecer.No, because it is only a cooling problem that usually goes away.
  • CSí, porque en este caso puede deberse a una mala combustión.Yes, because in this case it may be due to poor combustion.
Show answer

Correct answer

  • CSí, porque en este caso puede deberse a una mala combustión.Yes, because in this case it may be due to poor combustion.
Explanation

Black smoke from the exhaust usually shows poor combustion, because of too much fuel or not enough air, for example because of a dirty air filter or faulty injectors. It should be checked because it increases fuel consumption and pollution. Bluish smoke is the one that shows oil is being burnt.

Independent app: not affiliated with or endorsed by the DGT (Spain's Directorate-General for Traffic) or the Ministry of the Interior. The official exam is booked with the DGT and taken at its test centres. The questions here are practice material; the DGT's official question bank is not public.