Many of todays' engines utilize turbochargers to provide a boost of power and/or increase efficiency. A turbo, or turbine-driven forced induction device, functions by pushing extra air into the cylinders of your engine for increased horsepower by burning the fuel more efficiently.
While typically a long-lasting and reliable component, there are several common turbo problems that can lead to anything from diminished performance to destroying the engine.
Signs of a Bad Turbo
Paying close attention to how your engine is operating and performing regular service and inspections is a smart way to stay on top of engine maintenance and preventive care. Any noticeable change in the engine performance or sound means that something has changed and needs to be investigated. If you notice signs of a turbocharger problem, such as oil leaks or a change in the sound…it's critical to get it checked out as soon as possible. You should also be aware of the normal boost pressure the engine operates at…and investigate any major change in pressure or the cause of the Check Engine Light (CEL) or Malfunction Illumination Light (MIL).
Also keep an eye out for the following indicators of common turbo problems:
- Reduced Acceleration: Since the turbocharger is responsible for providing added power to your engine, one of the easiest ways to recognize they are failing is when you notice a lack of acceleration getting off the line as well as throughout the entire speed range.
- Increased Oil Burn: A bad turbo tends to burn through (or leak) oil more rapidly. Keep track of how often you need to add more oil and look out for leaks and signs of blockage and deposits.
- Smoke: The smell and sight of smoke coming from your exhaust pipe tells a story… When first starting your engine, White smoke is unburned fuel- until the engine warms up and the turbo is "up to speed" this is normal.
As the engine warms up, blue smoke is never a good sign, blue smoke indicates engine oil is present (bad rings, valve seals, or a major oil seal issue in the turbo).
Black smoke is unburned fuel that is wasted…this happens when there isn't enough boost air to burn the fuel completely- this could be a worn or defective turbo, or leaks or blockage in the piping or intercooler/aftercooler.
- Excessive Noise: Unusual noises coming from your engine are never good. But if you hear a loud whining sound, it could be from reduced airflow or lubrication to the turbo unit.
Reasons for Common Turbocharger Failures
Turbo problems are caused by a variety of factors such as a lack of lubrication, oil contamination, usage outside of standard specifications, and regular wear and tear. The following are some common turbo problems and failures:
- Cracked housings and/or worn seals allow air to escape and cause the turbocharger to work harder and wear down quicker.
- A buildup of carbon deposits and contaminants traveling through the system can damage inner engine components.
- The presence of foreign objects, such as dust or debris entering the turbine or compressor housing, can cause damage to the compressor wheel or nozzle assembly. (Some turbos spin more than 300,000 RPM…it doesn't take much at that speed to destroy a turbine or compressor wheel.)
- Leaks in the air intake system increase stress on the turbocharger as it works to compensate for the lack of air.
- Blocked or partially blocked diesel particulate filters prevent exhaust gas from flowing freely through the system, causing a variety of problems. The turbo spins as a result of the expanding hot air from combustion…when this air is restricted, the turbo cannot obtain the optimum speed, therefore the power is low, and black smoke is present…in extreme instances, the turbine (hot) side of the turbo can become much hotter than designed for, and seals become brittle and fail, causing everything from leaks to a possible run-away engine, which can overspeed and destroy itself.