A turbocharger failure doesn't always mean the turbo itself is the problem. Loss of power, smoke, unusual noises and boost faults can also be caused by hoses, sensors, intercoolers, oil-supply problems or other engine components.
At Bimmer Garage Nottingham, we specialise in BMW and MINI turbo failure diagnosis, servicing and repairs. Where a turbocharger requires specialist reconditioning, we work in collaboration with Midland Turbo.
BMW & MINI Turbo Failure Symptoms
A turbocharger problem may cause:
- Loss of power
- Poor acceleration
- Excessive turbo lag
- Loud whining or siren-like noises
- Grinding or rattling
- Excessive smoke
- Increased oil consumption
- Boost-pressure faults
- Engine warning light
- Limp-home mode
The combination of symptoms is important when diagnosing the fault.
How Do You Diagnose a Failed Turbo?
A proper turbo diagnosis should look at the entire turbocharging system, rather than simply replacing the turbo based on one symptom.
1. Diagnostic Scan
The first step can be checking the vehicle for stored fault codes.
BMW and MINI diagnostic systems may identify faults relating to:
- Boost pressure
- Airflow
- Turbo control
- Sensors
- Engine management
- Emissions systems
A fault code provides valuable information, but doesn't automatically prove that the turbocharger has failed.
2. Check Actual vs Expected Boost
Boost pressure is one of the most useful diagnostic measurements.
If the engine isn't producing the expected boost, the cause could be:
- Turbocharger wear
- Split boost pipe
- Intercooler leak
- Turbo-control problem
- Sensor fault
- Intake restriction
- Exhaust restriction
Comparing actual and requested boost can help narrow down the problem.
3. Inspect the Boost System
A leak in the boost system can make a healthy turbo appear to be faulty.
We can inspect components such as:
- Boost hoses
- Intercooler
- Intake pipes
- Connections
- Clamps
- Turbocharger housing
A damaged hose can cause significant power loss without the turbo itself being defective.
4. Inspect the Turbocharger
Where appropriate, the turbo can be physically inspected for signs of damage or abnormal wear.
Checks may include:
- Compressor wheel condition
- Turbine condition
- Shaft movement
- Housing damage
- Evidence of wheel-to-housing contact
- Oil contamination
Shaft movement needs to be assessed according to the specific turbocharger design. Some movement can be normal, so this isn't simply a DIY pass/fail test.
5. Check the Oil System
Turbochargers depend on adequate lubrication.
A diagnosis may therefore include checking:
- Engine oil level
- Oil condition
- Turbo oil feed
- Turbo oil drain
- Potential restrictions
- Evidence of oil starvation
If the turbo failed because of an oil-supply problem, that issue needs to be corrected before fitting another turbo.
6. Investigate Smoke and Oil Consumption
Smoke can provide useful information.
Blue or blue-grey smoke can indicate oil entering the combustion process.
A damaged turbo can potentially allow oil into the intake or exhaust system, but engine wear and other faults can cause similar symptoms.
Can a Turbo Failure Damage a BMW or MINI Engine?
Yes, potentially.
A severe turbocharger failure can allow excessive oil into the intake, cause turbocharger debris to enter the engine or result in significant oil loss.
On diesel BMW and MINI models, excessive oil entering the intake can potentially cause engine runaway.
If the vehicle develops heavy smoke, severe turbo noises, rapid oil consumption or uncontrolled engine revving, stop driving and arrange professional assistance.
Don't Replace the Turbo Before Finding the Cause
One of the most important parts of turbo failure diagnosis is determining why the turbo failed.
Possible causes include:
- Poor lubrication
- Incorrect engine oil
- Contaminated oil
- Restricted oil feed
- Blocked oil drain
- Excessive heat
- Bearing wear
- Foreign-object damage
- Boost-system faults
- Intake or exhaust restrictions
If the underlying problem isn't corrected, a replacement or reconditioned turbo can potentially fail again.
BMW & MINI Turbo Reconditioning
If diagnosis confirms that the turbocharger requires specialist reconditioning, Bimmer Garage Nottingham works in collaboration with Midland Turbo.
Where suitable, the turbocharger can be professionally assessed and reconditioned.
This can provide an alternative to automatically fitting a brand-new turbocharger.
Whether reconditioning or replacement is appropriate depends on the turbo's condition and the cause of failure.
BMW & MINI Turbo Diagnostics in Nottingham
At Bimmer Garage Nottingham, we can diagnose turbo-related problems on BMW and MINI vehicles.
Our checks can include:
- Diagnostic fault codes
- Boost pressure
- Turbocharger inspection
- Boost hoses
- Intercooler
- Turbo-control system
- Oil feed and drain
- Intake system
- Oil leaks
- Related engine faults
The exact diagnostic procedure depends on the BMW or MINI model and engine.
Turbo Failure Diagnosis: The Bottom Line
If your BMW or MINI has lost power, started smoking, developed a strange turbo noise or is using excessive oil, don't automatically assume the turbo needs replacing.
A proper diagnosis should establish:
Is the turbo actually faulty? What caused the failure? And has the problem affected any other part of the vehicle?
At Bimmer Garage Nottingham, we provide BMW and MINI turbo diagnostics and repairs, and work in collaboration with Midland Turbo for turbocharger reconditioning where appropriate.
Contact Bimmer Garage Nottingham with your BMW or MINI registration, mileage and symptoms for an accurate assessment.