hello world!

Why Turbos Fail

Long Island Turbo Repair Shop

Here are some common reasons why turbocharger engines fail, so you have a template on what to be on the lookout for when it comes to keeping your turbo engine running smoothly.

If you do happen to have turbocharger engine failure, do not hesitate to reach out to LI Turbo. Request a quote today for the parts and service you need.

Request a Quote

Obstructed Valves

An increase of pressure within the crankcase causes obstructed valves in the cylinder head, which can lead to a loss of oil to the turbocharger. This pressure prevents the oil from flowing back to the crankcase via the turbo drain tube. It also increases the pressure and temperature of the oil, which results in an oil leak at the compressor end of the turbocharger, causing blue smoke.

If obstructed valves are identified early enough, then changing the filter is often enough to solve this problem. However, if the oil loss has been happening for a while, often unnoticed, then the oil will carbonize behind the turbine wheel. This carbonization is what causes the turbo failure. When this happens, it is necessary to change the filter and the complete turbocharger.

Lack of Lubrication

A lack of oil supply to the turbo, which is essentially a lack of lubrication can result in catastrophic damage to the bearing systems. This damage can occur within seconds. When this lack of lubrication occurs, drivers experience issues such as a lack of power and vehicles smoking from the exhaust leading up to the failure of the turbo engine.

Oil Starvation

Signs of oil starvation includes discoloration to the thrust parts and the journal bearing diameter of the shaft and wheel.

Foreign Object Damage

A common mode of failure for turbo engines is from foreign object damage to the impellor blades on either side of the turbocharger. Both the air intake side of the turbo (compressor side) and the engine side of the turbo (exhaust side) sustain blade damage from foreign objects. Some signs of a problem with the turbo due to damage from an object includes loud noises such as whistling, or a lack of performance.

In the case of foreign object damage to the impellor blades on either side of the turbo, it is important to check the air filter for foreign objects. Also check the intake hose for debris and/or damage. Objects can also damage the EGR valve sticking due to high carbon/exhaust soot buildup. Any failure to clean or replace this valve can result in failure of the turbo engine.

In the case of object damage to the compressor wheel blades, it is crucial to check the air filter element, as well as the air filter housing, plus the intake hoses for dirt and damage. Any of these issues being prolonged will lead to turbo engine failure.

Blocked Engine Breather Assembly

Faulty electronic actuator boxes are common issues on turbochargers. Fault codes are normally identified when a diagnostic test is performed on the vehicle and this type of failure is often a result of a blocked engine breather assembly.

Carbon Buildup

On some turbochargers, carbon buildup around the variable vanes' assembly is a common mode of failure. The carbon buildup around the variable vanes is commonly referred to as suffering with "sticky vanes." This buildup restricts the movement of the actuator arm and reduces boost pressure, which can result in the vehicle being put into "limp home mode" by the engine management system in an effort to prevent further damage to the vehicle. Other signs for this carbon buildup includes "glow plug light" coming on and/or intermittent power loss.

Clogged CAM Cover

The engine breather assembly found on top of the CAM cover can clog, which causes the engine to perform less efficiently. This congestion then causes increased crankcase pressure, which creates an increased back pressure in the sump forcing the oil back up the oil return pipe to the turbocharger. Over time, escaping oil can build up carbon around the variable vane assembly, which restricts their movement. This restriction affects the operation of the electronic actuator generating the fault codes picked up on the diagnostic test. The end result may be a destroyed turbo engine or issues with the vehicle, like a lack of power and/or smoking from the exhaust leading up to the failure of the turbocharger.

Clogged Oil Drainpipe

Over time, the oil drainpipe has a tendency to clog, which causes increased oil pressure within the turbo engine. Due to the increasing pressure, it causes the oil to pass into the exhaust system and air intake of the engine. The result of this issue is blue smoke pumping from the exhaust. This problem can even happen during the process of fitting a new turbo engine, even when the problem has not previously happened before. If so, replacing the oil drainpipe is a must.

Clogged Oil Inlet Hose

The oil inlet hose has a tendency to clog from time to time. This is due to its proximity to the exhaust manifold. A clogged oil inlet hose will dramatically reduce the oil flow reaching the turbo engine and results in a lack of lubrication. When this happens, it is imperative to replace the oil inlet hose when the turbocharger is replaced or remanufactured.

Soot in the Oil

Many turbo engines are designed to work at high temperatures, so using good quality oil is essential in achieving peak performance. These turbos will have a filter installed on the oil feed pipe to the turbo and an integral filter/oil cooler in order to ensure that it performs efficiently. When you use a lower grade oil, you run the risk of causing a high concentration of soot in the oil if the engine runs on oil levels below normal. Then this soot blocks the filter that is installed in the turbo supply pipe, the oil cooler and main filter, which will cause the turbocharger to fail. The vacuum pump may also be impacted by the pollution of the soot in the oil.

Diesel Particle Filter (DPF) Issues

There are some turbo engines that have issues with the Diesel Particle Filter (DPF). If these issues are not quickly resolved, then it may lead to other problems with the turbocharger such as:

  • Blockage of the diesel particle filter, which results in warning lights on dash, loss of power, and limp home mode.
  • Inability to stop "Regeneration Mode," which results in diesel leaking into the oil and a lack of lubrication.
  • Carbon deposits clog the EGR valve.
  • Backpressure caused by carbon deposits, which leads to total turbo failure.
  • Damage to injectors caused by carbon buildup.
  • Damage to the engine seals, which causes over pressurizing.

It is important to identify the failure mode of the turbo and determine whether or not a DPF related issue is the cause of it. If the entire rotor assembly is OK and there are signs of overheating towards the turbine side of the core assembly, then the failure is likely to be caused by excessive exhaust gas temperatures. High amounts of carbon buildup within the mechanism and lever arms indicate a blocked DPF.

More About DPF Causing a Turbo Failure

Loose Nut Shaft

During the assembly of a turbo engine, a shaft nut will hold the compressor wheel and other rotor group parts onto the shaft. The shaft nut is a machined part, which need to be tightened to a specific torque in order to work properly. A shaft nut is normally left-hand thread, unless the rotor parts are reverse rotation, and is also referred to as a "locknut" or an "impeller locknut."

If there is any kind of resistance or locking up within the rotor, then the centrifugal force/inertia continues, leading the shaft nut to eventually come loose. When the nut shaft comes loose, it can result in catastrophic damage to the compressor wheel within seconds of the turbocharger starting up.

More About Loose Nut Shaft

cross linkedin facebook pinterest youtube rss twitter instagram facebook-blank rss-blank linkedin-blank pinterest youtube twitter instagram