Defective turbocharger: The 9 most common causes of turbocharger damage and repair

The causes of a turbocharger damage can be manifold. A precise fault analysis of the defective turbocharger is recommended in order to avoid generating new turbocharger damage within a short time after the repair or replacement of the turbocharger.

The 9 most common causes of defective turbochargers are

1. Damaged axial bearing and thrust washer of the turbine shaft
2. Damaged main bearing due to oil dilution
3. Damaged main bearing due to insufficient lubrication
4. Damaged main bearing due to oil contamination/foreign bodies
5. Damaged turbine geometry on the exhaust side
6. Damaged turbine geometry on the fresh air side
7. Overspeed damage to turbine shaft and housing
8. Oil leakage at the turbocharger
9. Damage due to excessive exhaust gas temperature

Tips:

• The 07eins turbo check! We carry out an expert analysis and inspection of defective turbochargers. Based on the cause of the damage, we recommend the correct procedure for replacing and exchanging the turbocharger.
• As replacement turbochargers for Volkswagen VW T5 2.5 TDI engines, we offer the double-tested and brand-new 07eins turbochargers for VW T5 2.5 TDI engines use.

The following is a detailed description of the 5 most common causes of damage to defective turbochargers and the corresponding measures to prevent new turbocharger damage:

 

1. damaged axial bearing and thrust washer of the turbine shaft

Description of the damage: The axial bearing of the turbine shaft consists of a thrust washer made of a special copper alloy. If the pressure in the exhaust gas flow increases excessively during operation, this leads to a load and displacement of the turbine shaft against this axial thrust washer. At a certain point, the oil pressure in the system is no longer sufficient to separate the bearing surfaces from each other, which subsequently leads to surface damage to the bearing material. The damaged surfaces cause a further localized drop in oil pressure, which accelerates the development of damage. The increasing friction leads to a drop in the turbocharger speed, which initially results in a loss of power and subsequently in the total failure of the turbocharger.

Cause: In the vast majority of cases, excessive exhaust back pressure is caused by a clogged diesel particulate filter. The wafer-thin channels in the filter fabric of the particulate filter can become clogged with soot and deposits, significantly reducing the cross-section for the exhaust gases to flow through. This reduction causes an increase in pressure, which leads to the damage chain described above.

Background: The clogging of a particulate filter, especially in diesel vehicles, can be caused by various factors. Here are some possible triggers:

• Short journeys: Diesel vehicles tend to produce more soot during short journeys and low operating temperatures. If the engine does not reach operating temperature sufficiently, this can lead to incomplete regeneration of the particulate filter, which in turn can lead to blockages.
• Missing or inefficient regeneration: Modern diesel vehicles are equipped with particulate filter regeneration systems, where temperatures in the exhaust system are increased to burn off soot deposits. If this regeneration does not work properly or does not occur often enough, this can lead to a blockage.
• Fuel quality: Contaminants in the fuel, such as water or particles, can affect the particulate filter. The use of low-quality fuel can lead to deposits in the filter.
• Malfunction of the exhaust gas recirculation (EGR): Improperly functioning exhaust gas recirculation can lead to more soot particles entering the combustion chamber and thus clogging the particulate filter more quickly.
• Defective injection nozzles: If the fuel injectors are not working properly, this can lead to incomplete combustion of the fuel, which can result in increased soot production and therefore faster clogging of the particulate filter.
• Vehicle age and mileage: As the age and mileage of a vehicle increases, the likelihood of particulate filter clogging can increase, especially if maintenance has been neglected.
• Driving style: A particularly aggressive driving style with frequent acceleration and braking can lead to increased soot production and thus to faster clogging of the filter.
• Lack of air: A lack of fresh air supply to the engine can lead to incomplete combustion and thus increase soot production.

Repair recommendation BEFORE installing a new turbocharger:

Repairing a clogged diesel particulate filter can vary depending on the severity of the clog and the specific conditions of the vehicle. Here are the most common approaches:

• Regeneration by forced drive cycle: Modern diesel vehicles have systems to automatically regenerate the diesel particulate filter. If the filter is slightly clogged, a forced driving cycle on the highway or a similar road at higher speeds can help to promote the combustion of soot particles and regenerate the filter.
• Cleaning by chemical additives: There are special chemical additives that can be added to the fuel to loosen deposits in the diesel particulate filter. These additives can help to clean the filter and enable improved regeneration. It is important to follow the manufacturer's instructions when using such additives.
• Professional cleaning systems: There are specialized workshops that offer professional cleaning systems for diesel particulate filters. These systems can clean the filter using compressed air, vibration or other methods. It is advisable to have this carried out by qualified specialists.
• Replacing the diesel particulate filter: In some cases, a severely clogged diesel particulate filter cannot be effectively cleaned and it is necessary to replace the filter. This is usually a more expensive option, but allows the filter function to be fully restored.
• Inspection and repair of system components: It is important to identify and address the causes of the filter blockage. This may include checking and repairing components such as the exhaust gas recirculation (EGR) or fuel injectors to ensure that the exhaust system is working properly.

 

2. damaged main bearing due to oil dilution

Description of the damage: The turbine shaft bearings consist of axial bearing washers and a radial material pairing for the central plain bearing of the shaft. A constant film of fresh oil ensures that the bearing materials made of a special copper alloy do not come into direct contact with the surface of the turbine shaft. If this oil film is interrupted or loses its lubricating properties due to chemical changes or contamination in the engine oil, this leads to contact between the bearing surfaces. Surface damage to the bearing material occurs in the affected areas. The damaged surfaces cause a further localized drop in oil pressure, accelerating the development of damage. The increasing friction leads to a drop in the turbocharger speed, which initially manifests itself in a loss of power and subsequently in the total failure of the turbocharger.

Cause: In these cases, the damage that has occurred indicates that the engine oil has insufficient lubricating properties. There are also other causes of damage to the main bearing (e.g. contamination in the oil or lack of oil itself), but the type and nature of the wear in this case indicates a lack of lubricating properties.

Background: The most common reason for a lack of lubricating properties is the dilution of the engine oil. Oil dilution in combustion engines occurs when fuel enters the engine oil and reduces the viscosity of the oil. In pump-nozzle engines, leaking injector seats of the pump-nozzle elements are very often the source of fuel leaking into the oil circuit. This dilution of the engine oil by the non-lubricating diesel fuel leads to a significant reduction in the lubricating properties of the engine oil in the long term and would explain the corresponding damage.

In principle, a lack of service should also be mentioned, which could cause very poor lubricating properties of the engine oil. If the engine oil change intervals are not properly observed, the properties of the oil deteriorate over the period of use. Engine oil that is clearly too old and therefore "worn out" also leads to similar damage patterns.

Other causes of oil dilution, although less common in the engines concerned, are

• Short-distance driving: Short trips often don't give the engine enough time to get up to operating temperature. A cold engine burns fuel less efficiently and unburned fuel can get into the oil and cause thinning.
• Faulty injectors: Faulty fuel injectors can result in fuel not being properly injected into the combustion chamber, which can lead to incomplete combustion and fuel residue in the engine oil.
• Defective fuel pressure regulator: A faulty fuel pressure regulator can cause the fuel pressure in the injection system to be too high, which can lead to excessive injection volume and an increased likelihood of fuel in the oil.
• Incorrect injection timing: Incorrectly adjusted ignition timing can lead to incomplete combustion and contribute to fuel leaking into the engine oil.
• Engine problems: Mechanical problems, such as leaking valve stem seals or piston rings, can cause fuel to enter the combustion chamber and ultimately get into the engine oil.
• Problems with the crankcase ventilation system: A defective or overloaded crankcase ventilation system can cause fuel vapors to enter the crankcase and condense with the engine oil.
• Malfunction of the exhaust gas recirculation (EGR): An improperly functioning EGR can lead to incomplete combustion and cause fuel to enter the engine oil.
• Excessive fuel pressure: Excessive fuel pressure in the injection system can cause fuel to enter the combustion chamber and accumulate in the engine oil.

Repair recommendation BEFORE installing a new turbocharger:

Carefully check the cause of the lack of lubricating properties of the engine oil using the points listed above. If there is a suspicion of diesel contamination through the seats of the pump-nozzle elements, we strongly recommend the use of our pump-nozzle bridge (PDE bridge) or our PDE body holder (PDE repair holder).

A complete oil and filter change should be carried out according to the manufacturer's instructions after the cause has been confirmed and eliminated by replacing or repairing the components.

 

3. damaged main bearing due to insufficient lubrication

Description of the damage: The turbine shaft bearing consists of thrust bearing washers and a radial material pairing for the central plain bearing of the shaft. A constant film of fresh oil ensures that the bearing materials made of a special copper alloy do not come into direct contact with the surface of the turbine shaft. If this oil film is interrupted or loses its lubricating properties due to chemical changes or contamination in the engine oil, this leads to contact between the bearing surfaces. Surface damage to the bearing material occurs in the affected areas. The damaged surfaces cause a further localized drop in oil pressure, accelerating the development of damage. The increasing friction leads to a drop in the turbocharger speed, which initially manifests itself in a loss of power and subsequently in the total failure of the turbocharger.

Cause: In these cases, the damage that has occurred indicates a lack of engine oil supply to the bearing. There are also other causes of damage to the main bearing (e.g. contamination in the oil or lack of lubrication properties of the engine oil due to fuel ingress), but the type and nature of the wear in this case indicates a lack of oil supply.

Background: The bearing surfaces of the turbocharger, as well as the entire plain bearings in the engine itself (camshafts, crankshaft, connecting rods, etc.), are supplied with a constant flow of oil by the oil pump during normal operation, which is what gives them their sliding and bearing properties. Parameters such as oil pressure, oil quantity and viscosity of the engine oil are crucial for the wear-free functioning of these highly stressed areas.

Very often, some core problems occur here, which also lead to the supply to the bearing points being impaired:

• Faulty oil pressure control valve: In modern vehicles, it is important that the oil pressure and quantity are within a precisely specified operating window. To achieve this, the oil pumps in the vehicles have special control devices, which are sometimes based on complex hydroelectric valves and can fail or deviate in their parameters in individual cases. If, for example, there is not enough oil pressure throughout the system due to a control valve shutting off too early, this can lead to the grinding damage at the bearing points described above.
• Worn oil pump: Similar to the damage caused by faulty control devices, a fundamentally worn oil pump can also be a reason why fluctuations in oil pressure and oil supply occur, which in turn leads to the same damage patterns. One reason for wear on the oil pumps can be a lack of engine maintenance and, in particular, exceeding the oil change intervals. In the long term, the reduced lubricating properties of the engine oil cause wear on the oil pump impellers and thus reduce the performance of the pump.
• Blocked/obstructed oil ducts: From the central pump, the oil flow is routed through various lines and channels in and around the engine to the required points. Contamination in the oil often causes the cross-sections of these lines to become constricted due to deposits and blockages with suspended particles. Due to the extreme heat development on the turbocharger, the supply and drain lines of this component are particularly badly affected. Lines to the main bearing of the turbocharger are often clogged with oil carbon, which leads to a reduced supply and localized lack of oil pressure. The bearing damage described is an inevitable consequence of this impairment of lubrication. It is therefore essential that you always replace the direct supply and drain lines of the turbocharger as a precautionary measure after any damage!
• Clogged/misplaced oil filter: A problem that should not be neglected is clogged oil filters, which mean that the required amount of engine oil can no longer be pumped through the filter and thus into the circulation system. The resulting lack of oil pressure leads to the damage described above.

Reasons for clogged oil filters can include

• Deposits and contamination: The main purpose of the oil filter is to filter contaminants and particles from the engine oil. However, over time, deposits, sludge or metal shavings can accumulate in the engine, clogging the oil filter and reducing its filtering capacity.
• Oil carbon formation: High temperatures in the engine can lead to the formation of oil carbon. These deposits can accumulate in the oil filter and block its pores, resulting in reduced permeability.
• Ageing of the filter: Oil filters have a limited lifespan, and over time the filter media can become worn or clogged. An old or worn oil filter can become clogged more quickly and lose its efficiency.
• Wrong type of oil: Using unsuitable or poor quality engine oil can cause the oil filter to clog more quickly. The wrong oil can create more deposits and sludge that clog the filter.
• Engine problems: Mechanical problems in the engine, such as abrasion of components, can lead to increased particle formation. These particles then enter the oil system and can clog the filter.
• Incorrect filter size: Using the wrong oil filter or one that is not suitable for the vehicle can lead to problems. A filter that is too small can clog more quickly and fail to do its job effectively.

Repair recommendation BEFORE installing a new turbocharger:

A thorough check of the cause of the missing oil pressure using the points listed above. Due to the frequency of this problem, we recommend always replacing all engine oil supply and drain lines to the turbocharger as a precautionary measure! A complete oil and filter change in accordance with the manufacturer's specifications is recommended once the cause has been confirmed and eliminated by replacing or repairing the components.

 

4. damaged main bearing due to oil contamination or foreign bodies

Description of the damage: The turbine shaft bearing consists of axial bearing washers and a radial material combination that serves as a central plain bearing for the shaft. A constant film of fresh oil is used to ensure that the bearing materials, consisting of a special copper alloy, do not come into direct contact with the surface of the turbine shaft. If this oil film is interrupted or loses its lubricating properties due to chemical changes or contamination in the engine oil, this can lead to contact with the bearing surfaces. This in turn leads to surface damage to the bearing material in the affected areas. The damaged surfaces cause a further localized drop in oil pressure, which accelerates the development of damage. The increasing friction leads to a drop in turbocharger speed, which initially manifests itself in a loss of power and can ultimately lead to total failure of the turbocharger.

Cause: In these cases, the resulting damage shows signs of wear on the bearing surfaces due to contact with foreign bodies (i.e. contamination of the engine oil). Other causes can also lead to damage to the main bearing (e.g. lack of lubrication properties of the engine oil due to fuel ingress or poor/interrupted oil supply), but in this case the type and nature of the wear indicates the ingress of foreign bodies.

Background: The bearing surfaces of the turbocharger, as well as the entire plain bearings in the engine itself (camshafts, crankshaft, connecting rods, etc.), are supplied with a constant flow of oil by the oil pump during normal operation, which gives them their sliding and bearing properties. If this oil flow contains particles or foreign bodies, the bearing surfaces are attacked by these and can lose their mechanical properties, which ultimately leads to bearing failure.

There are several known sources of foreign bodies or particles in engine oil:

• Oil carbon deposits: The oil flow from the central pump is routed through various lines and channels in and around the engine to the required points. Due to impurities in the oil, there is often a risk that the cross-sections of these lines will be constricted by deposits and suspended particles. The inlet and outlet lines of the turbocharger are particularly susceptible to such blockages caused by carbon deposits due to the intense heat generated by this component. On the one hand, this can impair the supply to the turbocharger, but on the other hand, parts of this oil carbon can also become detached again during operation, whereupon they are drawn into the bearings and cause the damage described above.
• Damaged/worn oil filter: Another point is defective oil filters, which in normal operation basically fulfill the task of immediately filtering any suspended particles, particles and dissolved foreign bodies from the engine oil. If the filter properties are inadequate, the filter lamellae damaged or perforated, foreign bodies can no longer be reliably removed from the oil. On their way through the oil lines, these get into the turbocharger bearings and cause the damage described above.

Repair recommendation BEFORE installing a new turbocharger:

A thorough check of the cause of the missing oil pressure using the points listed above. Due to the frequency of this problem, we recommend always replacing all engine oil supply and drain lines to the turbocharger as a precautionary measure! A complete oil and filter change according to the manufacturer's specifications is recommended after the cause has been confirmed and eliminated by replacing or repairing the components.

 

5. damaged turbine geometry on the exhaust side

Description of the damage: The turbine wheel blades on the exhaust side show considerable damage. These turbine blades are set in rotation by the exhaust gas flow from the combustion chambers and generate the necessary speed on the main shaft of the turbocharger in order to compress the charge air on its inlet side. The exhaust side of the turbocharger is a highly stressed component due to the extreme heat generated by the combustion gases. However, the damage detected on your turbocharger clearly indicates that the impellers or parts of the VTG mechanism have been damaged by external foreign bodies.

Cause: Several scenarios can be considered as the cause of foreign body damage. In any case, the damaging element is a part made of comparatively hard material that could enter the exhaust gas flow and damage the turbine geometry by hitting the impellers.

Background: When the exhaust side of a turbocharger is damaged, it can generally be assumed that the foreign object responsible originates from inside the engine. Due to the undamaged compressor geometry and the need to pass through the combustion chamber, it is rather unlikely that the foreign body traveled through the entire engine tract via the intake. For these reasons, sources within the engine, in particular within the exhaust manifold, must be considered for the origin of the foreign bodies.

Possible sources:

• Breakage/fragments of the exhaust manifold: By far the most common cause of foreign objects are parts of the exhaust manifold. Contrary to initial assumptions, modern exhaust manifolds are not usually made of solid metal, but are constructed in several layers. Due to the high heat load and the stressful environment in this area of the exhaust system, corrosion and cracking very often occur on the inside of the manifold wall. If this process continues, individual parts, splinters and fragments of the manifold wall may be carried away by the exhaust gas flow during operation. Their next path leads directly into the turbine housing of the turbocharger, where they cause the damage to the turbine geometry described above. Due to the frequency of this cause, we recommend a thorough inspection of the inside of the exhaust manifold every time the turbocharger is replaced!
• Breakage/broken pieces of the exhaust valves: Much rarer but nevertheless known are also breakages/breakage pieces of the exhaust valves, which can mix into the exhaust gas flow in an identical way to the manifold parts.
• EGR valve components/deposits: The exhaust gas recirculation uses a valve unit to ensure that parts of the exhaust gas flow can be fed back into the combustion process. In this way, it is possible for parts of the valve mechanism to become detached and enter the exhaust gas flow. The subsequent damage to the turbine geometry is identical. The deposits that often form in the entire area of the system can also come loose in fragments and damage the turbine blades.

Repair recommendation BEFORE installing a new turbocharger:

A thorough check of the source of the foreign bodies using the points listed above. In particular, the issue of damaged manifold insides is a very common problem. A complete oil and filter change according to the manufacturer's specifications is recommended after the cause has been confirmed and eliminated by replacing or repairing the components.

 

6. damaged turbine geometry on the fresh air side

Description of the damage: The compressor wheel blades on the fresh air side show considerable damage. These compressor wheel blades are set in rotation by the main shaft of the turbocharger and generate the speed required to compress the charge air accordingly. The damage detected on your turbocharger clearly indicates that the aluminum impellers have been damaged by external foreign bodies.

Cause: The turbocharger's turbine shaft rotates at more than 100,000 rpm during normal operation so that the intake air can be compressed to the required boost pressure by the impellers on the compressor side. Due to the material properties and the decisive specific weight, aluminum is generally used as the material for the compressor wheel. If the smallest foreign bodies in the air flow hit the compressor wheel, which is rotating at high speed, this usually has extreme effects on the material itself. A wide range of damage is known, from deformation and chipping to breakage of one or more guide vanes. In any case, the turbocharger loses its function due to the damage itself and the resulting imbalance of the entire shaft.

Background: Foreign bodies can enter the intake tract of a combustion engine in various ways.

Here are some possible causes:

• Air intake: Foreign objects can enter the intake tract through the normal air intake process. This can be dust, leaves, insects or other particles that are present in the ambient air.
• Leaking seals: Leaks in the intake system, such as leaking seals at connection points or between different intake components, can cause foreign bodies to enter the intake tract.
• Inferior air filter: A poorly maintained or inferior air filter cannot effectively protect against foreign objects. If the air filter is damaged or dirty, larger particles can pass through.
• Missing or damaged air filter box: A missing or damaged air filter box allows direct access of foreign objects to the intake tract. This can be caused by accidents or improper maintenance.
• Incorrectly fitted or damaged intake pipes: Incorrectly fitted or damaged intake pipes can result in foreign bodies entering the intake tract directly.
• Parts or particles of the air duct itself: Broken fastening clips and parts of system components such as mass air flow sensors and intercoolers can get into the air flow, as can sensor elements or particles from connectors or cable guides.
• Parts of the crankcase ventilation system: To achieve the vacuum required in the crankcase during operation, it is connected to the intake area of the engine via a hose connection. If the components, hose guides or connections of the crankcase ventilation are damaged, splinters and parts of them can get into the intake air in this way.

Repair recommendation BEFORE installing a new turbocharger:

Carefully check the source of the foreign bodies using the points listed above. The entire air supply system from the filter, intercooler and piping through to the turbocharger itself must be cleaned extremely carefully and thoroughly. Even the smallest and at first glance harmless particles (paper/adhesive tape/foam etc.) can cause massive damage to the turbine shaft at the current engine speeds.

A complete oil and filter change in accordance with the manufacturer's specifications must be carried out after the cause has been confirmed and eliminated by replacing or repairing the components.

 

7. overspeed damage to the turbine shaft and housing

Description of the damage: The turbine and compressor housing, as well as the impellers themselves, show signs of damage, indicating that the turbocharger is running at too high a speed. Basically, by flowing through the turbine side of the turbocharger, the exhaust air generates the necessary speed of the main shaft, which can then compress the fresh air to the required boost pressure using the connected compressor wheel. Both the turbine side made of steel (heat development) and the compressor side made of aluminum (mass properties) are exposed to extreme operating conditions. Speeds of more than 100,000 rpm are regularly reached in normal operation and cause extraordinary stress on the turbine shaft. The wall thicknesses, alloys and tolerances of modern superchargers are concentrated in a very narrow manufacturing range. If the permissible speed values are exceeded, massive consequential damage, often combined with the complete destruction of the turbocharger, is the result. In your case, clear indications were found that the safe operating speed had been exceeded. Grinding marks on the impellers on the inside of the housing as well as broken or deformed guide vanes are a common sight here.

Cause: The permissible maximum speed of the turbine shaft has been exceeded and the resulting forces have damaged parts of the compressor wheel, the turbine wheel and the insides of the compressor and exhaust housing.

Background: The speed of the turbocharger depends on countless factors.

However, a few key points can be summarized:

• The VTG adjustment: The VTG (Variable Turbine Geometry) adjustment regulates the speed and effect of the turbocharger by adjusting the position of the guide vanes on the exhaust side. If parts of this adjustment corrode or the guide vanes themselves wear out, this can result in the turbocharger speed to be regulated being significantly too high.
• The pressure side of the charge air piping: If there is a leak in the charge air lines (hole in the charge air cooler/ruptured charge air hose/faulty connection point), the turbocharger control system may attempt to achieve the required boost pressure even though air is escaping at the points described. This can cause the engine speed to rise above the permissible maximum and lead to the damage described.
• Engine management/chip tuning: Very often, performance increases are achieved by third-party providers via changes to the charge air volume or boost pressure. The necessary increase in the speed of the turbocharger to achieve the new air volume/pressure level can result in the turbocharger being used outside its permissible operating limits.

Repair recommendation BEFORE installing a new turbocharger:

The cause of the excessively high turbocharger speeds based on the points described above must be carried out conscientiously. Modified engine software (chip tuning) is by far the most common cause of the damage described above. The engine software and the proper functioning of the control units involved must be checked!

A complete oil and filter change in accordance with the manufacturer's specifications must also be carried out after the cause has been confirmed and eliminated by replacing or repairing the components.

 

8. oil leakage at the turbocharger

Description of the damage: A turbocharger in perfect condition is always dry and has no traces of oil on the fresh air or exhaust side. The bearings of a turbocharger consist of a complex axial bearing with precisely machined thrust washers made of specially alloyed materials and a rotor shaft radial bearing that is exposed to extremely high speeds and various thermal loads. If the lubrication of this bearing fails because the oil is not available in the correct quantity as it is pressed out of the turbocharger housing, total failure is quickly the result.

Cause: To ensure perfect lubrication of this bearing at all times, the oil quantity between the oil supply before the bearing and the oil return after the bearing must be in a precisely defined ratio. If, for example, engine oil builds up in the oil return line because it is not possible to drain into the oil pan for one of the reasons listed below, engine oil will leak out of the turbocharger, causing the turbocharger bearing to fail completely.

Background: If oil leaks from the turbocharger, this can be caused by various sources of error:

• Crankcase ventilation: If there is a defect in the crankcase ventilation, undesirable excess pressure can quickly build up in the crankcase, which means that the oil from the turbocharger return line does not drain back into the oil pan, but is forced out at the turbocharger housing partition by the excess pressure.
• Oil return: If the turbocharger oil return line on your vehicle is blocked, the engine oil which should flow back into the oil pan through the return line after storage cannot drain out. As fresh engine oil from the inlet is constantly present at the bearing via a reduction with a defined pressure, but cannot drain off, the engine oil builds up more and more until it finally escapes at the housing split.
• Internal oil leakage: A turbocharger works on the principle of "equal pressure sealing", which means that exhaust gas pressure and fresh air pressure must always be in the correct ratio to each other to ensure an internal seal so that no oil escapes from the axial bearing. If this is not the case, e.g. because a leaking intercooler is installed, oil may leak out on the fresh air side.
• Oil level too high: If the engine oil level in your engine is permanently too high, this can also result in oil escaping via the turbocharger return line. One reason for an excessively high engine oil level can be, for example: oil dilution with fuel due to leaking pump/nozzle elements, a defective fuel pressure regulator or frequent short journeys.

Repair recommendation BEFORE installing a new turbocharger:

Carefully determine the cause of the oil leakage from the turbocharger using the points described above. In most cases, there is a problem with the oil return to the oil pan, which is why a thorough check of all oil lines is mandatory before a new turbocharger is installed.

A complete oil and filter change in accordance with the manufacturer's specifications must also be carried out after the cause has been confirmed and eliminated by replacing or repairing the components.

 

9. damage due to excessive exhaust gas temperature:

Description of the damage: An excessively high exhaust gas temperature leads to thermal stress, which in turn leads to damage to the turbocharger components. The exhaust gas housing of a modern turbocharger is made of heat-resistant materials such as cast iron or stainless steel. The robust design of the exhaust gas housing is crucial to ensure the durability of the turbocharger under the high operating conditions. However, if the exhaust gas temperature exceeds the specified values, the materials are overloaded, resulting in a defect. 

Cause: There are several causes for an excessively high exhaust gas temperature, ranging from an incorrect air/fuel mixture to excessively high boost pressures or defective components in the exhaust system. The more air is present during combustion, the higher the temperature generated during this process, which results in the specified exhaust gas temperature being exceeded.

Background: Excessive exhaust gas temperature can cause various types of damage to the turbocharger. The most common types of damage are listed in detail below:

• Manipulation of the engine software: Performance increases are very often achieved by third-party suppliers by changing the charge air volume or boost pressure. The necessary increase in the injection and fresh air volume inevitably causes the exhaust gas temperature to rise.
• Lubrication damage: High exhaust gas temperatures can cause the lubricating oil to overheat, which in turn impairs its lubricating ability. If the lubricating oil in the turbocharger is overheated or even burnt, oil carbon can form which attacks the bearings of the turbocharger and results in total failure.
• Material fatigueConstantly high temperatures can lead to signs of fatigue in the materials of the turbocharger, especially if they are not designed for such temperatures. This can lead to cracks or other structural damage.
• Turbocharger overheatingIf components of the exhaust system are defective or offer too little passage, the exhaust gas temperatures are also too high, causing the turbocharger to overheat, which can lead to impaired performance and total failure.
• Reduced service life: In the long term, repeated exposure to high exhaust gas temperatures can significantly shorten the service life of the turbocharger.

Repair recommendation BEFORE installing a new turbocharger:

Carefully check the cause of the increased exhaust gas temperature using the points described above. Often, the engine software has been manipulated or components in the exhaust system are defective. A complete oil and filter change must be carried out in accordance with the manufacturer's specifications after the cause has been confirmed and eliminated by replacing or repairing the components.

 

Conclusion on the 9 most common causes of turbocharger damage:

Turbocharger damage can have many causes, but nevertheless, defective turbos can be traced back to the 9 most common damage patterns. A precise damage analysis must be carried out in order to prevent the turbocharger from failing again. This is where the 07eins turbo check with a detailed root cause analysis. Once the cause has been identified and eliminated, we recommend the double-checked and brand-new 07eins turbochargers for VW T5 2.5 TDI engines to be used.