Troubleshooting Auto Turbochargers
The turbocharger is the heart of the turbo system, forcing pressurized air into the engine for substantially increased horsepower. However, due to the extreme heat and pressure the turbocharger experiences under normal operation, problems with the internal turbo components can develop over time. Additionally, problems with the intercooler system and other supporting components can cause your turbocharger to perform poorly. Troubleshooting many of the common problems that develop with turbo systems is made easy by observing your vehicle's boost gauge, as it gives you a real-time readout of the turbocharger's performance. If your vehicle lacks a boost gauge, you can still troubleshoot most turbocharger issues by paying close attention to the turbo's sound and performance.
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Instructions
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Inspection
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1
Ensure that the engine is fully cooled down so that you can safely inspect the turbo system. Open the hood and check every vacuum line for signs of damage. Since vacuum lines are generally made of rubber, they are prone to developing cracks over time due to the extreme temperatures reached in the engine bay. Make sure each vacuum line is securely connected to its proper location. A loose or damaged vacuum line will allow for boost leaks, which lead to numerous turbocharger performance problems.
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2
Inspect the turbocharger unit for signs of oil or coolant leakage. If there is fluid buildup on or around the turbo unit, it likely indicates worn internal seals. Have your turbocharger rebuilt as soon as possible if this is the case, as improper lubrication will lead to worn internal components over time, as well as overheating issues.
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3
Remove the turbocharger so that you can inspect the internal components. The removal process varies between engines, so refer to a shop maintenance manual if you are unsure of the required procedure. Generally, you have to remove the intake system, exhaust heat shield and any other components obstructing movement of the turbocharger. Then, detach all oil and coolant lines from the turbo housing. (Some engines require that you drain the oil and coolant before detaching the lines.) Finally, remove the four bolts that secure the turbocharger to the exhaust manifold, then remove the entire turbo unit.
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4
Grip the shaft that connects the turbines by reaching into the turbocharger inlet. Check for shaft play by attempting to wiggle the shaft up and down. Any movement in the shaft indicates worn bearings in the turbocharger that must be replaced immediately to avoid damage to the turbines or housing.
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5
Peer into the turbocharger inlet and outlet to inspect the internal components. Nicks in the turbine blades or housing indicate shaft play, as the turbine blades are likely rubbing against the housing when in operation. Alternatively, any debris in the turbo housing can cause nicks and dents on the turbines.
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6
Look for any oil buildup inside the turbo housing. The presence of oil on the turbines or housing indicates that the shaft seals are leaking and should be replaced immediately. This is especially common on the compressor side of the turbocharger due to the pressure levels it experiences.
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Inspect the entire turbo housing closely for signs of cracking. Cracked housing can be caused by the extreme heat levels generated by the turbocharger. If cracks are present, the housing needs to be repaired or replaced immediately to avoid worsening pressure leaks and other performance issues.
Driving Tests
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Start your vehicle and allow the engine to reach normal operating temperature. Drive to a safe and legal location at which you can accelerate the engine to redline.
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Accelerate to redline and note any unusual noises coming from the turbocharger. An excessive whining noise indicates that the bearings are becoming worn. If the bearings are failing, you will hear an occasional metallic grinding noise. This is due to the turbo shaft or turbines grinding against the turbocharger housing.
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10
Note any acceleration issues the engine experiences. Failing turbo components and boost leaks will make the engine feel hesitant under full acceleration, as the turbocharger is unable to provide the proper level of boost.
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11
Note boost spiking or creeping behavior as indicated by the boost gauge. Often caused by an improperly actuating wastegate or boost controller, a boost spike causes the turbo pressure to briefly rise several psi above the proper setting when the engine is fully accelerated. Extreme boost spikes can lead to a damaged turbocharger and/or internal engine components. Boost creep is a situation in which the turbo pressure reaches its preset maximum value, then slowly increases until the engine redline. This is often due to the wastegate failing to open properly.
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