A small leak in the ducting for the turbo would most likely produce which symptom under load?

• A. A restricted air cleaner
• B. Worn turbocharger bearings
• C. Turbine wheel contact with housing
• D. Small leak in the ducting for the turbo

Answer: (A)

When a turbo system has a small leak in its ducting, some of the compressed air is lost before it can reach the engine. Under load, the engine demands a large amount of air, so that leak becomes noticeable as a restriction in the intake path. The air that should be flowing through the system is diverted or lost, making the intake feel restricted, which is why a restricted air cleaner is the symptom you'd expect to observe first.

Worn turbo bearings would typically cause a whining noise and possible oil reports rather than a straightforward intake restriction. Turbine wheel contact with the housing would present a harsh mechanical fault, likely with obvious noise and damage. Saying there’s a small leak in the ducting is describing the fault itself rather than a symptom, whereas the restricted air cleaner captures the effect on the airflow path under load.