If your car is suffering from a loss of engine power, there’s a chance your turbo has a fault. Luckily, there are many ways to detect different types of turbo faults, and we’ve collected them all in one place.  

Keep reading to learn about different types of turbos, common faults, as well as how you can detect them before they become too much of a problem for you and your car.  

What is a turbo? 

A turbo (or turbocharger) is a type of forced induction system that is commonly used in modern engines to increase their power output and efficiency. A turbo fault can affect performance, efficiency, and reliability.  

Turbos are an integral part of your car’s engine. They help deliver more power to your drivetrain, improve your car’s fuel efficiency, and reduce your overall emissions – meaning the condition of your car’s turbo will have a significant bearing on its performance.   

Turbos use exhaust gases from the engine and send them through a series of moving turbine wheels. This pressurises the air before introducing it into the engine.  

Turbochargers vs turbo bearings 

Before diving into the different turbo types, we’ll quickly define the difference between turbochargers and turbo bearings.  

Both are parts of the complete turbocharger system but oversee different functions.  

Turbochargers are devices that force more air into the engine’s combustion chamber. The main parts of the turbocharger system include a compressor and turbine. 

Turbo bearing refers to the specific bearing within the turbocharger. The bearings are used to support the rotating shaft, reduce friction, and ensure a smooth overall operation.  

What are the different types of turbochargers?  

There are six main styles of turbochargers. Some are designed for high-performance cars, some are more affordable, and some are made for diesel cars. Here are the main types to know: 

• Single-Turbo 
• Twin-Turbo 
• Twin-Scroll Turbo 
• Electric Turbo 
• Variable Geometry Turbo 
• Variable Twin Scroll Turbo 

What are the different types of turbo bearings?  

Turbos come in two main types: hydrodynamic journal-bearing systems and ball-bearing systems. Here’s a quick rundown of each and their differences. 

Hydrodynamic Journal Bearings 

Hydrodynamic journal bearings are the more common type of turbo bearing. They’re made of a journal (shaft), which rotates within a sleeve while oil is fed into the sleeve and the journal gap.  

Hydrodynamic journal bearings are more straightforward in design and affordable to manufacture. They’re also very durable and able to handle high loads.   

Ball Bearings 

Ball bearings are a newer innovation in turbo technology. Unlike hydrodynamic journal bearings, this design uses a set of small balls to support the shaft. These reduce friction and provide a smoother operation. 

Like hydrodynamic bearings, ball bearings also need lubrication. However, the design has less friction and surface contact.  

Ball bearings give faster response times, increased efficiency, and reduced turbo lag due to the lower friction levels. This makes them better for high-performance cars.  

What type of turbo bearing do I have? 

Since there are different types of turbos, you need to know which your car has before you fix any faults. There are a few ways to work out what you have, but here are the best options: 

• Consult the car owner’s manual 
• Contact your dealership 
• Look for the turbocharger part number 
• Ask a qualified mechanic to inspect the turbocharger 
• Research your car make and model online

If you’re not comfortable or experienced with car mechanics, you should work with a mechanic to find your turbo type. They can provide professional advice and perform any necessary maintenance. 

The most common turbo faults & causes 

Unfortunately, turbochargers fail from time to time. The first step to fixing your turbo is working out the problem. See the most common turbo faults and causes below.  

1. Insufficient engine lubrication  

The oil inside your engine keeps its moving parts lubricated and prevents rust and corrosion. The turbo is no exception – with a gas turbine wheel rotating at high speeds, it's essential that the wheel’s bearing remains well lubricated.  

If poor quality or inappropriate oil is used in your car’s engine, the turbo bearings may experience too much friction. Consequently, the turbine won’t be able to rotate correctly. This results in insufficient air being delivered to the engine’s cylinders, therefore reducing engine power.  

It should be noted that even if you use the right sort of oil, over time, it can become contaminated with solid particulates. Similarly, it may evaporate to a point where it’s no longer effective. This is why changing your engine oil every 3000 miles or so is widely recommended - dependent on the manufacturer’s recommendations.

2. Obstruction due to foreign objects  

If something gets caught in your turbo, it can form a blockage that restricts the flow of gases.   

When a turbo becomes restricted in this way, your engine cannot benefit from the pressurised air flow that your turbo is supposed to deliver. Common objects found stuck in turbos include leaves, feathers, and metallic pieces from inside the engine.   

There’s a chance that something has become lodged in your turbo if you notice a significant drop in engine performance combined with a strange clattering or rattling sound coming from your engine.  

3. Lack of pressure in the compressor  

The pressure inside the turbo’s compressor determines how much air is being forced into the engine. If the pressure is too low, the engine will receive insufficient air, and the power output will suffer.   

Low compressor pressures can be caused by the compressor wheel either not spinning at all or spinning too slowly. If the compressor wheel isn’t moving, this usually indicates a problem with the bearing inside the turbo.   

However, if the compressor wheel is spinning too slowly, this is likely a result of a blockage in the system, a decrease in engine vacuum, or a problem with the turbo’s wastegate. Significant reductions in engine power or strange engine sounds typically accompany this type of turbo fault.   

4. Exhaust Gas Recirculation (EGR) failure  

The EGR system regulates the exhaust gas sent back into the engine. An EGR system is used with a turbo to maintain correct air-fuel ratios within the engine cylinders.  

The engine performance will suffer if the EGR system isn’t working properly, typically caused by sticking in the EGR valves. If not enough exhaust gas is recirculating into the engine, it may have difficulties starting and poor running, leading to the deposition of carbon in the turbo, dramatically affecting its performance.   

On the other hand, too much exhaust gas recirculating into the engine will produce excessive nitrogen oxides and coke, significantly reducing engine efficiencies.   

How to diagnose turbo faults  

Suspect you have a turbo fault? Here are some typical signs of a turbocharger problem. 

Loss of engine power  

You should notice an increase in engine power as soon as you press down on the accelerator. If your car feels unusually sluggish, there’s a good chance a faulty turbo is to blame. Remember, the turbo delivers pressurised air into your engine, so any turbo faults will influence engine power.  

Difficulty accelerating  

Like a loss of engine power, a faulty turbo will result in difficulty accelerating. Acceleration will feel slower and louder, and your car may judder.   

Blue or black smoke coming from your exhaust  

Blue or black smoke from your exhaust is symptomatic of cracks in your turbo’s housing or blown internal seals. These cracks or blown seals will cause oil to leak into your exhaust system, producing distinctive blue or black smoke as it burns off.  

Excessive turbo whistling  

You shouldn’t notice any whistling coming from your car’s turbo. If you do hear a significant amount of whistling, something’s likely wrong. In this instance, turbo faults are usually caused by excessive exhaust gas temperatures.   

Fluid leakage from the turbocharger and other areas

If you notice significant fluid leakage around your engine, your turbocharger is almost certainly the culprit. Different types of fluids can leak from the turbo. The most common leaks are oil and coolant, though it’s also possible for petrol to leak from the turbo.  

As with blue or black smoke, this indicates there are cracks or blown seals in the turbo’s housing.  

Different types of turbos & common faults: The bottom line 

A car’s turbocharger is an integral part of the engine that helps to improve performance and fuel efficiency whilst reducing emissions. If your turbocharger isn’t operating properly, you’ll notice reduced engine power, difficulty accelerating, and other symptoms, such as a smoking exhaust or leaking fluid.   

In short, there are many different types of turbo faults, each representing a serious problem for your car.  

If you notice any of the issues described in this article, taking your car to a mechanic for a diagnosis is critical. A turbo replacement can cost upwards of £700, so to make this cost more affordable, split it into monthly payments with Bumper, completely interest-free!  

To apply for a credit limit and see dependable garages and dealerships in your area, enter your vehicle registration and postcode on our website.  

Author - Joseph Law

Joseph has been writing about cars for over seven years and writing for Bumper for over two, blending his passion for automobiles with a talent for storytelling.

Joseph has written about engineering and cars for Autozilla, Komaspec, and several engineering manufacturers. When he's not writing or tinkering with one of his five cars, Joseph dreams of owning an Alfa Romeo 33 Stradale.