Turbo Failure: 11 Reasons For A Bad Turbo And Why It Happens

Turbo failure and bad turbos: Naturally aspirated engines used to run the show. Then downsizing and environmentally conscious motoring came along and made everything run on turbos. Don’t believe us? Just check all the engines that you find in modern vehicles. Very rarely will you spot a line up of naturally aspirated engines as you once would. But it is not all bad, turbo charged engines are more fuel efficient, they provide the same power with much less cylinders and space, and some would even claim they are much more fun to drive. But having a turbocharger in your engine also means one thing, you now have a whole new component that is prone to failure and quite expensive to replace.

Before we dive deeper into what causes a turbocharger failure, we must note that turbo failures are not something you should be afraid of. Yes, it does happen, but it mostly happens on vehicles with high mileage and vehicles that have not been properly serviced. 

Quick recap: How Does a Turbo Work

Every internal combustion engine on this planet uses a mixture of fuel and air to produce power that is later transmitted to the wheels. In order to produce more power, you need to burn more fuel per second and if you want to do that, you also need more air. That is where a turbocharger comes into play.

A turbocharger forces more air into the engine by using the exhaust to spin an air compressor or an air pump which force feeds into the engine. That is why you also hear turbo engines being called “forced induction engines”. The concept is really simple but super effective, the engine is then forced to burn more fuel per second and in return return more power. 

To do so, a turbocharger spins at incredibly high rates (up to 300,000 rpm) and they operate under extreme temperatures and pressure. In order to function correctly, everything has to go according to the plan.

Symptoms of a turbo failure

Loss of power and acceleration

If you are used to driving your car with a healthy turbo then you will most definitely know when something is wrong with the turbocharger. You will not feel the turbo kick in anymore, the acceleration will be horribly poor and most of the time your car will not even let you drive in anything other than “limp” mode.

Whistling and whining engine noise

Any turbocharger can give out a slight whistling noise (especially big turbo’s), especially when it gains rpms under a heavy acceleration. But an unhealthy turbo, that is most likely going to fail soon, is whining and whistling like there is no tomorrow. If you notice that the whistling and whining appeared or if it is getting worse, we highly recommend you get your turbo checked out by a professional.

Blue smoke coming out of the exhaust pipe and heightened engine emissions

If the seals around the turbo degrade, or if there are any cracks in the housing of the turbo you can expect to see clouds of (usually blue) smoke behind you as you accelerate. This means that oil has entered the exhaust where it burned off due to heat. Visit a mechanic as soon as you see blue clouds of smoke behind you.

Check engine warning light

Modern engines will not let you drive around with a malfunctioning or a blown turbocharger. The car will either ignite the check engine warning light or enter limp mode to prevent further engine damage. If your car does allow you to drive with a blown turbo, we would advise that you do not do it. Visit a mechanic as soon as possible.

turbocharger impeler blades

Reasons why a turbocharger fails

A turbocharger will almost never (less then a 1% chance) fail because of a manufacturer’s fault. Garret, the world’s leading manufacturer of turbochargers names 3 killers of turbos: oil starvation, oil contamination and foreight object damage.

Restricted oil feed

Engine oil is to a car, like blood is to a human body. Without it, components fail and one of them is a turbocharger. A turbo is constantly fed fresh engine oil to support its function and to keep it cool when it runs at full power. If any of the oil feed tubes get blocked by contaminants (mainly carbon deposits) or if the tubes get damaged or bent, your turbo is going to fail quickly. Without a source of engine oil, the turbo overheats which damages the casing and the turbocharger internals. This can also happen if the amount of engine oil is insufficient, if the engine oil filter is blocked or damaged and if the oil pump of the engine is malfunctioning. If you just got a replacement turbocharger, make sure that the person replacing the turbo has primed the replacement turbocharger with oil.

Oil contamination

Oil contamination is considered to be the most dangerous turbo killer out there. Oil contamination can occur due to a high carbon buildup in the engine, accidental contamination of oil while working on the car, engine wear can leave metal shavings to travel around the engine with the oil and lastly contamination can also have a bigger effect if oil degrades or if the engine oil filter is old and damaged. Oil that is highly contaminated with carbon from ineffective combustion acts as an abrasive on the inner parts of the turbo. This slowly and gradually leads to a turbo failure.

Oil leaks

Oil leaks at the air compressor end or at the turbocharger end can also lead to premature turbo failure. Have your mechanic inspect any leaks on both ends of the turbocharger,

Harmful driving habits

There are several driving habits that are hurtful to your turbo. We will cover all of them in detail later but what is more common is that no one will teach you how to drive a car with a turbo.

Age related wear

Every mechanical component on your car has a certain life expectancy. The same is true for your turbocharger. You can expect that a healthy engine and a healthy turbocharger will last somewhere around 150,000 miles or 250,000 kilometers.

Over-speeding

While this is more common on trucks and semi-trucks, all cars with a turbo can cause damage to the turbocharger by over-revving the engine behind its “red” limit. This causes the turbocharger to spin at rates above its manufacturing limit. This overboots the engine and can also lead to oil starvation.

Other reasons

A blocked catalytic converter can suffocate your turbocharger by limiting the airflow it needs, a damaged or blocked intercooler can also have a big impact on the state and life expectancy of a turbo. Introduction of foreign objects into the turbo intake system can also have a catastrophic consequence on the internals of the turbo (blades, bearings). A damaged turbocharger must be replaced to prevent further damage to the engine in an event of a complete failure.

How to avoid turbo failure

How to prevent oil starvation that causes turbo failure

The first thing to do here is some preventive maintenance. Make sure that all oil feed tubes are clean or replaced if necessary. Clean any and all carbon deposits that could starve the turbocharger of oil. Make sure that the engine’s oil pressure is correct and that oil supply to the turbo is in working order. When you fit a new turbocharger, make sure that a new oil filter and new oil is added to the engine.

How to prevent oil leaks that cause turbo failure

The first thing to do here is check the exhaust system for any leaks. When that is determined, make sure that there are no blocks in the air and oil drain systems.

How to prevent engine overspeeding

This is a very rare occurrence, but if it does happen once, you should immediately determine why overspeeding occured. One of the reasons for overspeeding could be leaks in the air intake system, a blocked wastegate can also be the culprit but most importantly in modern cars make sure that all electronic sensors and the ECU that prevent overspeeding are in working order.

How to prevent oil contamination and avoid turbo failure

Oil contamination is mostly a consequence of carbon deposits and sludge that finds its way into the oil and oil inlet tubes. Make sure that the engine is running on correct engine oil, make sure that carbon accumulation is kept under control and that all the inlet pipes are clean and replaced if need be.

How to prevent turbo failure by foreign object damage

The most important thing to do for preventing any foreign objects entering the air intake system is to regularly replace air filters, gaskets and ensure that all air intake hoses are in good condition. Even small foreign objects can cause great damage to the turbocharger. And by small we mean smaller than a grain of salt. 

How to drive a car with a turbocharger to prevent early turbo failure

If you bought a new car with a turbo engine, we can bet that no seller gave you pointers on how to handle and drive a car with a turbocharger. An exact same thing happens when you buy a car with a DSG transmission, no one teaches you how to drive a car with that transmission. What no one tells you, is that replacing turbochargers prematurely is good for business. And dealerships love nothing more than replacing turbos and earning those sweet $ on parts and labor.

Avoid hard accelerations when the car is cold

When your car stays parked overnight or for longer periods, all the engine oil accumulates in the oil sump at the bottom of the engine and when you first turn it on, it take some time for the oil to circulate around the engine and reach the turbo. This is the reason why taking it easy as you first ignite a cold engine is crucial to prolong the life of your turbo and many other engine components. Accelerating hard from the get-go is a sure way to starve your turbo of oil and cause unnecessary engine.

Avoid extensive engine idling

Prolonged engine idling can create a vacuum within the turbine and lead to damage. While giving a few seconds of idle tile before heading off is ok, letting your car idle for 20 minutes before leaving is complete nonsense. 

Never shutdown a hot engine (never!)

This one is probably the most important tip of them all. After you finish driving for an extended period (20+ minutes) make sure you give your turbo a time to cool off. This is how to do it; After you arrive at your destination, park the car and leave the engine running for a good minute or two. It does wonders for the health of your turbo. By doing this, the turbocharger stops spooling while fresh, cool oil circulates around the turbo and gives it the chance to cool off.  Make this a habit! 

Is it worth buying a cheap, remanufactured turbo?

We’ve been through this roller coaster with cheap fuel injectors and cheap turbochargers. And the answer we can give you is no, it is not worth it! Never. A cheap turbo unit will not only give you a weakened performance, it will also be prone to premature failure and it will also pose a risk for potential engine damage if it fails while driving. Do not even get us started on the expense of having to pay for two turbos in the end and double the cost of replacement labor.

mercedes V8 with biturbo engine

Frequently asked questions

Can a bad turbo damage the engine?

Yes, a bad turbo can lead to engine damage, especially if the problem is ignored. A piece of a turbo blade/impeller can also get sucked into the intercooler or catalytic converter.

What happens when a turbo goes bad?

A bad turbo will lead to a loss of engine power, increased exhaust smoke and emissions, a check engine warning light will ignite on the dashboard and you might also hear whistling and whining sounds coming from the turbocharger itself.

Can bad turbo seals cause blowby?

Bad turbo seals can lead to blow-bys. Worn out turbo seals cause the boost pressure and exhaust gasses to enter the oil return to the crankcase which in return causes blow-bys.

Can a bad turbo cause white smoke coming from the exhaust?

While it is not common that a bad turbo will cause white smoke to exit the exhaust, it is possible. More common is gray or blue smoke which means that the car is burning excessive oil.

Can a bad turbo cause increased oil consumption?

Yes, a bad turbo can be the culprit behind excessive engine oil consumption. Worn turbo seals, or oil return pipes can leak oil which results in excessive oil consumption.

Can a bad turbo cause engine overheating?

No, a bad turbo will not cause the engine to overheat.

Is having a turbo bad for your engine?

No, if your car was designed to run with a turbo, then it is constructed in a way that handles the forced induction of compressed air. Fitting an aftermarket turbocharger to a naturally aspirated engine however, is bad for your engine.

How to diagnose a bad turbo?

You will first hear whistling and whining noises coming from the turbo. You might also feel that your car is lacking power. You can then inspect the turbo visually and continue the diagnosis at your mechanic.

How does a bad turbo sound?

A bad turbo will start whistling and whining. These sounds will get louder and more profound as damage increases overtime.

How to diagnose bad turbo seals?

Bad turbo seals are easily diagnosed by locating oil leaks around and under the seals. You might also see gray or blue clouds of smoke behind your car if bad oil ring seals leak oil into the exhaust system.

What does a bad turbo sound like on a diesel?

A bad turbo on a diesel engine sounds just like a bad turbo on a petrol engine. A bad turbo causes whistling and whining noises which become more and more profound over time as damage increases.

What does a bad turbo actuator sound like?

99% of the time a bad turbo actuator will not be releasing any sounds. You will experience other symptoms such as loss of power, low or overboost and engine warning lights.

What does a bad turbo look like?

A bad turbo can be inspected visually. You can inspect the seals around the turbo for any leaks and the internal blades or the impeller of a turbo for any signs of damage. Looking at a turbo from a distance will not tell you if it is bad or not.

Where’s the turbo in a car?

A turbocharger is always mounted to the exhaust manifold of the car. Sometimes the turbo can be hidden out of sight when you open the hood. If the turbo is visible, it depends on the engine construction.

Can a bad turbo cause bad mpg/fuel efficiency?

Yes, a bad turbo can cause increased fuel consumption. The engine will still prepare the air/fuel mixture as if the turbo is working properly but all that it is doing is flooding the engine with fuel that is not getting combusted because the turbo fails to provide the needed amount of air for the mixture.

Is it bad to drive with a bad turbo?

Yes, driving with a bad or a blown turbo is bad for your engine. In fact it can lead to complete engine failure so we advise against it. If you can, drive your car to the mechanic and leave it there until it is repaired.

What is the difference between turbo and biturbo?

The difference between turbo engine and bi-turbo engine is in the number of turbochargers. As the name suggests, a bi-turbo engine is constructed with 2 turbos that increase the engine power immensely. A turbo engine is fitted with a single turbo unit.

What are common bad turbo bearing symptoms?

Bad turbo bearing symptoms are the same as the symptoms of a “bad” turbo. You will experience loss of power, lesser acceleration, blue exhaust smoke and other problems.

Conclusion

Having a turbo engine is nothing but joy. The pulls you experience when that turbo kicks in is nothing short of amazing. But it is all fun and games until you start experiencing first signs of a bad turbo. If you do experience those signs, do not ignore them and hope for the best. The first warning signs are just an indication of a coming turbo failure so make sure you get them fixed before there is greater damage and bigger repair bills.