Symptoms may include reduced engine power, abnormal noises, blue smoke emitting from the exhaust, and unstable idling; in severe cases, the vehicle may even become completely inoperable. Once a turbocharger fails, it directly compromises the engine's air intake efficiency and combustion process, subsequently triggering a cascade of performance and safety issues.

Depending on the severity of the malfunction, the following typical symptoms may manifest:

**Significant Power Loss:** Damage to the turbocharger leads to insufficient air intake, resulting in reduced power output and sluggish acceleration.
**Abnormal Noises:** Wear on the internal impeller or bearings may generate whistling, grinding, or metallic clanking sounds.
**Oil Leaks and Oil Consumption:** If the turbocharger's shaft seals are damaged, engine oil may seep into the intake tract or combustion chamber; this results in **blue exhaust smoke** and an abnormally high rate of oil consumption.
**Unstable Idling or Stalling:** Abnormal intake pressure disrupts the air-fuel ratio, causing the engine to shake or vibrate at idle, or even stall unexpectedly.
**Increased Fuel Consumption and Worsened Emissions:** Incomplete combustion not only increases fuel consumption but also leads to exhaust emissions exceeding regulatory limits.
**Catastrophic Secondary Damage (in Extreme Cases):** For instance, a fractured rotor could physically destroy the engine, or extreme heat could cause oil "coking" (carbonization), leading to lubrication failure and further damage to the bearing system.
In certain specialized scenarios—such as a turbocharger failure occurring during the flight of a military drone—the malfunction could result in the aircraft losing control and crashing. The U.S. Air Force once reported an incident involving an MQ-1B "Predator" drone that, after encountering turbulence and suffering a turbocharger failure, ultimately stalled and crashed into a mountain.

It is worth noting that these symptoms are not exclusive to turbocharger failures; issues within other engine systems (such as sensor malfunctions or air intake leaks) can also manifest with similar signs. Therefore, professional diagnostic tools and procedures are required to accurately identify the root cause of the problem.