Turbo Malfunctions, Effects and Causes

Turbos are used in internal combustion engines to ensure that combustion is at optimized values and to increase the performance of the engine. A turbo can increase power output by 15-25% over a naturally aspirated engine. The turbo is rotated by exhaust gas, so it does not draw power from the engine like a belt-driven supercharger system. A turbo, on the other hand, doesn’t provide extra thrust until the throttle valve opens and exhaust flow increases. When this happens, it starts to rotate and push more air into the engine. Turbos can spin at 200,000 rpm and even higher. But it takes a few seconds for them to reach these speeds. The central structure of the turbos includes the air suction wheel (compressor side), the exhaust gas suction wheel (Turbine side) and the shaft to which they are connected (See Picture 1, 1.1). Depending on the structure and function of turbos, they have a lifespan during operation in the engine. In practice, there are various risk factors that can cause premature failure of turbos. In case of a malfunction, the prerequisite for a successful repair and rectification process is to find the root cause of the malfunction. Otherwise, the newly installed turbo may start to work improperly and malfunction in a short time. In this brochure, we will explain some problems that may occur and their possible root causes to help you.

Improper-Inadequate Lubrication Conditions:

Insufficient lubrication is one of the most important factors that cause turbos to malfunction. When lubrication conditions deteriorate, it is inevitable for turbos to fail. The biggest reason for this is that they operate at high speeds.


Due to damage to the turbo bearing, the intake and exhaust wheels may hit the turbo housing. This effect can be understood if there are signs of wear on the turbo housing and deformation of the impeller.

If the turbo shaft rotates improperly due to mixed lubrication conditions, the suction pressure of the turbo will decrease and the performance of the engine will decrease.
Insufficient turbo air intake may result in black smoke coming out of the exhaust. Because not enough air will be able to reach the combustion chamber for the fuel sent. This means that the rich air-fuel mixture is disrupted.

When there is insufficient lubrication, color change may occur on the surface between the turbo shaft and its bearing due to heat generated by friction. If the resulting temperature reaches serious levels, the bearing material may begin to stick to the shaft surface.