How to tell if you need a new turbo

How to tell if you need a new turbo

A turbocharger improves your car’s power and fuel efficiency. They’re usually pretty reliable, but when they fail, the effect can be devastating to your car.

What is a turbo?

A turbocharger or ‘turbo’ uses exhaust gases to power a turbine that compresses air before it enters the engine’s piston. In a regular engine, working at normal atmospheric pressure, air is simply drawn into the engine on the piston’s downward stroke. The higher-pressure air pushed into the intake by the turbo enables the engine to burn fuel more efficiently and results in greater power.

Turbos are common on diesel engines, particularly larger ones. Because they use exhaust gases to drive the turbine, they don’t load the engine. This makes them more efficient than superchargers, which are mechanically driven and have to deliver more power than they require from the engine to work properly in the first place. There are pros and cons to each; the mechanical connection means that a supercharger doesn’t have a ‘lag’, whereas if you stamp on the gas you will notice a delay before your turbocharger delivers the goods.

What are the signs your turbo is suffering?

Turbos are generally very robust. They have to be: powered by exhaust gases they have to be capable of withstanding extremely high temperatures, and the turbine can spin at an incredible 200,000 rpm. Failure is possible, though, for a number of reasons. There are two main ones to look out for: worn bearings and damaged seals.

Loss of acceleration is an obvious result of a damaged turbo, since its job is to increase the power output of your engine. However, this could be down to any number of reasons, hence there are two other symptoms to watch for:

  • A rattling or whining noise, or
  • Clouds of blue smoke coming from your exhaust.

These are sure-fire reasons to suspect your turbo is on the brink of giving out, potentially causing catastrophic damage to your car.

Bearing trouble

One of the most common ways a turbo can fail is when its bearings become worn. If that happens you may notice a whining noise coming from it; if you ignore this for long enough, the whine will develop into a loud howl. This is caused by the impeller blades hitting the housing of the turbine, wrecking them both. What you really want to avoid is any bits breaking off and being thrashed around inside the turbo at 200,000 rpm.

If things go wrong it probably won’t happen suddenly – you’ll get some warning of impending doom as the whining noise builds. But once there’s any real damage there’s little chance of repairing your existing turbo, and you will need to find a new one (they’re readily available second-hand). The moral is to stop and repair or replace the turbo as soon as you can.

Damaged seals

Another common source of turbo failure is the seals. When this happens, oil can leak into the intake and will be compressed with the air that the turbo sends to your engine. The visible result of this will be dense clouds of oily blue smoke coming from your exhaust. You’ll also start going through oil like there’s no tomorrow. Less obvious, but far more significant, is the damage that this will do to the engine. It can destroy your catalytic converter, and various sensors and other components will receive a thick and unwelcome coat of the black stuff, rendering them incapable of doing their job.


Turbos are not particularly prone to failure but if they do stop working properly the damage that can be caused – either to the turbo itself or the engine – can be significant and extremely expensive. If you notice any of the signs above, you should have it checked out immediately before it results in far worse problems.


This article was supplied by used car turbo location specialists, BreakerLink, who are linked to 100’s of breaker yards across the UK and have over 30 years of experience into the used car parts service