Why Do Turbochargers Fail? The Most Common Causes Explained
A Turbocharger Usually Fails for a Reason
When a turbocharger fails, many owners focus immediately on the damaged component.
The shaft.
The bearings.
The compressor wheel.
The oil leak.
But the more important question is often:
What caused the damage?
Turbochargers operate as part of the engine’s lubrication, intake and exhaust systems. A turbo uses exhaust energy to rotate the turbine, which is connected to the compressor by a common shaft. The compressor then increases the amount of air delivered to the engine.
That means conditions throughout the engine can affect turbocharger life.
Understanding the cause is essential because replacing the turbo without correcting the underlying problem can expose the replacement to the same failure.
- Oil Starvation
A turbocharger depends on engine oil for lubrication.
The rotating assembly operates under extreme conditions, and insufficient oil can damage bearing surfaces very quickly.
Possible causes of inadequate oil supply include:
- Restricted oil-feed lines
- Blocked passages
- Incorrect installation
- Improper gaskets
- Low engine oil
- Lubrication-system problems
- Failure to prime components properly during installation
Oil starvation is one of the major causes of turbocharger failure.
If a turbo has failed from lack of lubrication, simply installing another unit without correcting the oil-supply issue is a major risk.
- Contaminated Oil
Oil can be present and still cause damage if it is contaminated.
Particles traveling through the lubrication system can damage the turbocharger’s bearing system.
Contamination can result from:
- Poor engine maintenance
- Degraded oil
- Engine wear
- Debris from a previous failure
- Contamination introduced during repairs
- Dirty components or oil passages
Oil contamination is another major turbocharger failure mechanism.
This is why an oil and filter change may be part of the process when addressing certain turbo failures.
- Foreign Objects Entering the Compressor
The compressor wheel rotates at extremely high speed.
It does not take a large object to create meaningful damage.
Debris entering through the intake can strike compressor blades, creating:
- Chipped blades
- Bent blades
- Imbalance
- Reduced boost
- Vibration
- Bearing damage
Foreign-object damage is one of the primary categories turbo specialists should consider during diagnosis.
A damaged compressor wheel should lead to inspection of the air filter, intake piping and other upstream components.
Find out how the object reached the turbo.
- Debris Entering the Turbine Side
The turbine side can also suffer foreign-object damage.
Material coming from the engine or exhaust side can strike the turbine wheel.
Again, replacing only the damaged turbo does not answer the underlying question.
Where did the debris originate?
If that source remains, the replacement may be vulnerable.
- Restricted Airflow
A dirty or clogged air filter can make it harder for the engine and turbo system to receive the airflow they need.
Mike Turbo identifies dirty or clogged air filters as one of the conditions that can contribute to turbocharger problems and recommends regular filter maintenance.
Inspect:
- Air filter
- Intake tubing
- Compressor inlet
- Collapsed hoses
- Restrictions
- Loose or damaged connections
Turbo diagnosis should always include the intake system.
- Boost Leaks
If compressed air escapes between the turbocharger and the engine, the system will not deliver the expected boost.
Possible leak points include:
- Charge-air hoses
- Boots
- Clamps
- Intercooler
- Intake connections
This can lead to loss of power and may cause the turbo system to operate under conditions different from what was intended.
Do not condemn the turbo before pressure-testing the charge-air system where appropriate.
- Exhaust Restrictions
The turbine is powered by exhaust gas.
Conditions downstream can therefore influence turbo operation.
On modern diesel engines, excessive restriction in the aftertreatment system can be particularly important.
Mike Turbo’s technical guidance specifically discusses blocked diesel particulate filters as a possible contributor to turbo-related problems through increased exhaust backpressure and heat.
A replacement turbo should not be installed without considering the condition of the exhaust system when symptoms suggest a restriction.
- Excessive Heat
Turbochargers naturally operate at high temperature.
But abnormal heat conditions can accelerate damage.
Potential contributors include:
- Engine overheating
- Exhaust problems
- Improper operation
- Performance modifications
- Lubrication problems
- Severe duty cycles
Elevated temperatures can damage internal bearing-system components and contribute to excessive shaft movement and catastrophic failure.
The engine’s cooling and lubrication systems therefore matter to turbocharger durability.
- Turbo Overspeed
Every turbocharger has an operating range.
If a turbo is forced to rotate faster than intended, durability can be compromised.
Overspeed conditions may result from:
- Incorrect turbo sizing
- Improper tuning
- Severe boost leaks
- Control-system faults
- Wastegate problems
- Performance modifications
Excessive pressure ratio can contribute to turbo overspeed and reduced durability.
Performance modifications should be engineered as a complete system rather than by simply increasing boost.
- Improper Installation
A new turbocharger can fail because of installation errors.
Examples include:
- Dirty oil-feed lines
- Incorrect gaskets
- Uncorrected oil-drain problems
- Foreign material in the intake
- Contaminated intercooler or piping
- Failure to identify the cause of the previous failure
The complete engine system should be inspected before turbo replacement.
Oil, air, exhaust and crankcase problems can mimic or cause turbocharger issues.
- Normal Mechanical Wear
Turbochargers are mechanical devices.
Components can wear over time.
However, when a turbocharger fails prematurely, assuming “it was just old” can be an expensive mistake.
Inspect the evidence.
Wear patterns often provide clues about the underlying cause.
What Should You Do After a Turbo Failure?
Before installing another turbocharger:
Inspect the lubrication system
Verify clean and adequate oil supply and proper drainage.
Inspect the intake system
Look for contamination, broken filters and foreign-object entry.
Inspect charge-air piping
Check for leaks and contamination.
Inspect the exhaust system
Identify restrictions, leaks and aftertreatment problems.
Inspect the failed turbo
The damaged components may tell the story.
Correct the cause
Only then should the replacement or rebuilt turbo be installed.
Rebuild or Replace?
Once the failure has been diagnosed, the turbo itself can be evaluated.
Mike Turbo’s rebuilding process includes disassembly, inspection, replacement of appropriate service components and balancing of rotating parts.
If major components remain serviceable, rebuilding can make sense.
If damage is extensive, replacement may be the better decision.
Final Thought
A failed turbo is evidence.
Do not throw the evidence away before understanding what happened.
Replacing the failed turbo solves the immediate problem. Finding the reason it failed protects the next one.