There are many causes that can lead to a turbo failing but what are the main causes that can be seen after the failure happens. Turbochargers themselves are very simplistic pieces of equipment. All they really do is move air, it is not magic and there are not really that many moving parts. The process of designing a turbo is difficult with years of research into every element of the creation. Once they are built it is just a matter of maintaining them with proper services.
When it comes down to the turbo failure on a motor there are only 4 main reasons that caused failure. The first and most common reason for failure is metal fatigue over time. This will happen to all turbos eventually due to the expansion and contraction of the metal in the unit over time. Eventually over time the metal will become brittle and being to crack or crumble, usually starting with the impeller. Proper maintenance on a turbo will slow this process but in the end it cannot be avoided.
The second major type of failure is oil starvation, this occurs when the oil flow to the turbo stops. With no oil flowing to the turbo the bearings will become under-lubricated and will either seize up or just fall apart. Oil starvation can be seen when taking the turbo apart and inspecting the shaft of the turbo. When the shaft shows discoloration or scaring oil starvation is what killed this turbo. This can be cause due to low oil pressure, a blocked oil line or oil sludging. Oil sludging is caused by the turbo burning the oil that is in the unit and then it is pumped back into the oil pan. Usually the sludge is due to the car being shut off when the turbo is excessively hot and the oil sits in the turbo and burns. Then once the car is started it is pumped back into the system, this can be an issue for the engine as well as the turbo.
The third major reason for failure in a turbocharger is over-heating. While this may sound like a strange thing to worry about in a unit that gets hot enough to glow red, it is an issue. Many modern turbos use engine coolant pumped through them to keep the turbo within operating range. When the flow of coolant stops or is hindered it is just a matter of time before the turbo gets too hot and cooks the bearings inside. Again this can be seen by discoloration on the internal pieces of the turbo unit.
The last and final common cause of failure in turbochargers is foreign objects. The internal parts of a turbo spin around 30-50,000 RPM and if something like a rock or other debris were to enter the system it will cause serious damage. Basically a turbo is very intense fan just imagine if you threw a brick into a house fan. Think of the damage, well that is exactly what will happen to the impeller of the turbocharger. This can be detected if there are dents in the impeller blades and sometimes all of the blades get chewed off completely.
Making sure to check and determine the reason for failure is the best way to make sure that the replacement won’t fail for the same reason. An automotive turbo can cost upwards of $2,000 and a truck turbo can fetch prices in the $10K range so failure can be a costly repair. All of the failures listed here besides normal wear will void the seller warranty. In other words if the cause of the failure is not determined you could be stuck with a huge repair bill that could have been easily avoided.
