What is an indication of a failing turbocharger?

A failing turbocharger can often exhibit a phenomenon known as turbo lag, which is an increased delay between stepping on the accelerator and the engine's response. This can occur due to several reasons related to the malfunctioning of the turbocharger, such as issues with the bearings, wastegate, or the turbo's ability to spool effectively. When a turbocharger is not functioning properly, it struggles to generate the necessary boost pressure quickly enough, leading to noticeable lag in acceleration, which is especially evident during rapid throttle changes.

In contrast, excessive boost pressure may indicate that the turbocharger is still functionally sound but over-boosting, rather than failing. Abnormal engine noises might suggest other issues occurring within the engine that are unrelated to the turbocharger’s health specifically, such as problems with the engine bearings or valve train components. Lastly, higher fuel efficiency is typically a result of a well-functioning turbocharger that enhances engine performance and efficiency, rather than a sign of a failing component. Thus, turbo lag in acceleration is the most direct and consistent symptom of a turbocharger that is experiencing problems.