Turbo failures often are misunderstood. Many mistakenly believe something is faulty with the turbo. The reality is, though, it’s rarely the turbo. More often, failure happens for a non-turbo-related issue. Meaning, generally turbos don’t fail on their own—something is causing the failure.
Our Turbo Experts have identified the most common failure modes for turbos.
Being aware of these failure modes will help enthusiasts and technicians identify the root cause of the problem—armed with that knowledge you can avoid these mistakes, saving time and money in the long run.
FAILURE MODE #1: Lack of Lubrication – Low Oil Pressure
When you have lack of lubrication or intermittent low oil pressure you ultimately have oil starvation inside the turbo. The direct metal-to-metal contact inside your turbo bearings causes friction and high temperatures, resulting in bearing material transfer onto the shaft and vice versa. The inner components start to show evidence of tempering colors from the excessive heat. This can cause shaft seizure or breakage due to oil starvation.
FAILURE MODE #2: Improper Weight, Quality or Fuel Dilution of Oil
Whether the oil is old, contaminated or the incorrect type, it can lead to turbo failure quickly. Poor oil quality can block oil feed passages, smear the thrust bearing pad (only applies to journal bearing turbos) or cause oil build-up or worn bearings that cut off oil supply. This is why we have manufacture recommended oil change intervals and manufacture recommended oil for your specific vehicle. Note: Thrust bearings are not used in ball bearing turbos.
FAILURE MODE #3: Abuse – Fast Cold Starts or Hot Shutdowns
In harsh weather conditions, operators should allow time for the oil to start flowing and reach operating temperature before loading the engine. After operating under heavy boost, let it idle 30-60 seconds before shutting down, or perhaps when you're close to your destination, go easy on your vehicle allowing it to cool down before shutting it off. Different applications will have different requirements, but it's a good practice to limit yourself to part throttle (50% at most) until the engine reaches operating temperature, and to do the same a few minutes prior to shutting the engine off. Fast cold starts and shutdowns lead to premature engine wear and can eventually lead to turbo failure.
FAILURE MODE #4: Poor Engine Maintenance – Dirty/Contaminated Oil
Poor engine maintenance results in contaminated oil, with tiny hard particles that enter the turbo’s bearing system. This can cause scratches or grooves in the bearing surfaces, or result in wearing to the point that the wheels rub the end housings. This is why you always use a brand new oil pump after you rebuild an engine that's had any type of failure, and if you're installing a turbo on a freshly rebuilt engine, do yourself a favor and install a filter inline with the turbo's oil feed line, as the engine break in material will wreck the turbo and most turbo manufactures do not cover oil contamination related failures under warranty. NOTE: turbo manufactures also do not cover oil starvation related failures because it's another mechanical issue causing the turbo to fail, so keeping the in-line oil feed filter free of foreign object debris is critical!
FAILURE MODE #5: ECU/Fuel Calibration Changes – (Excessive EGT)
The exhaust gas temperature (EGT) is the temperature of the exhaust gases as they exit the combustion chamber entering into the turbo. When the EGT exceeds the original design limit due to improper tuning or wastegate / boost controller setup issues, it can cause cracking in the turbine housings, overheating and premature failure. The cheapest tuning shops / e-tuners usually end up costing the most money. Ask for application specific references and about relevant training and industry certifications.
FAILURE MODE #6: Foreign Object Damage
Don't be that guy who uses every engine bay surface as a tool shelf when working on your vehicle, doing this eventually this leads to leaving something behind in the engine bay, followed by expensive repairs.
Loose hardware left in the exhaust manifold or air cleaner or other foreign material will
lead to turbo damage.
Compressor side: Objects such as shop towels, nuts and bolts can enter the inlet and
cause damage to the compressor wheel blades.
Turbine side: Valves, valve seats, piston rings or broken manifold pieces can damage the inlet edges of blades. The damage is not always recognized if the turbine wheel is still able to rotate. Often, the turbine housing must be removed to see the damage.
FAILURE MODE #7: Other Defective Engine Components
Turbo failure often is the result of other defective engine components, including:
- Leaking inlet manifold
- Clogged air filters
- Lack of air filter
- Obstructed oil supply lines (bent, kinked lines, improper gaskets)
- Faulty oil pump (oil starvation)
- Incorrect turbo oil restriction
- Engine break in material (oil contamination)
- Clogged turbo oil feed line filter
- Faulty PCV system
- Improperly set up boost control system
- RTV used in place of a proper gasket (obstructed oil drain or feed lines)
- Gasket failure
- Oil leaks
- Incorrect ECU calibration for your modifications. Evan's Tuning explains further how to pick a tuning shop in the video below.
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