What are Turbochargers?
Turbochargers also commonly known as “Turbo” are induction machines that increase the efficiency of the internal combustion in a vehicle’s engine by forcing more air into the combustion chamber.
Before you fit a replacement turbo, you first need to determine what caused the turbo to fail. The causes for turbo failures fall under the following five categories:
Impact Damage
How do foreign objects damage turbos?
Failure of the turbo can be caused by foreign materials/objects entering the turbine/ compressor, damage can be caused by foreign objects that get pulled into the air intake.
What are the causes of impact damage?
- Items get pulled into the air intake because of the poor quality of a damaged air filter.
- Small particles enter the intake due to damaged hoses.
- Gasket material entering the intake.
- During servicing items such as nuts, bolts, washer, etc are left in the intake pipe during servicing.
- Broken engine components, e.g. injector nozzle, valves, or particles of the damaged piston.
- Particles from a former turbocharger failure.
Prevention of turbo failure caused by impact damage.
- Ensure all air hoses are in good condition and free from blockages.
- Always replace old gaskets with new gaskets to ensure a perfect seal.
- Dispose of the old air filter and replace it with a new air filter.
- Ensure that there are no turbo/ engine particles in the system from the previous failure, before fitting the replacement.
Oil Contamination
What causes contaminated oil?
- A damaged or blocked oil filter.
- High carbon build-up in the engine can quickly contaminate even new oil.
- During servicing, accidental contamination of new oil can occur.
- A malfunctioning oil filter bypass valve.
- Engine wear, leaving particles in the oil.
- Degraded oil due to excessive temperatures or extended service intervals.
Preventing turbo failure caused by contaminated oil.
- Ensure new oil and a new oil filter are used when fitting a new turbo., as recommended by the vehicle manufacturer.
- Ensure the correct oil is used for the engine.
- Ensure the oil inlet pipes are cleaned/replaced, to eliminate any carbon accumulation or sludge that could enter the turbo.
Oil Leaks
What causes oil leaks at the compressor end?
- A Blocked air intake filter.
- Blocked or damaged air intake pipe or hose.
- A possible air leak on the intake hoses or a leak at the intercooler.
What causes oil leaks at the turbine end?
- A Leak in the exhaust system.
- A Leak in the EGR system.
What causes oil leaks at both the compressor and turbine end?
- A restriction can occur in the oil drainpipe from the turbo to the engine.
- Restriction in the engine breather.
- Damage to the turbo’s rotating parts, and excessive bearing clearance.
- Incorrect turbocharger fitted.
Preventing turbo failure caused by oil leakage.
- Ensure there are no blockages/restrictions in the air and oil drain systems.
- Ensure there are no leaks in the exhaust system.
Oil Starvation
What causes oil starvation?
- The oil level in the sump is low.
- A flow restriction due to a bent in the oil feed pipe.
- Carbon build-up in the oil feed pipe.
- Applying silicone to the oil inlet gasket can cause blockage.
- Incorrect oil inlet gasket restricting oil supply.
- A blocked or damaged oil filter.
- Worn or damaged oil pump.
- Failure to prime the replacement turbo with oil during fitting.
Preventing turbo failure caused by oil starvation.
- Refrain from using silicone on oil gaskets; it can easily become separated and block oil passages.
- Ensure the oil inlet pipes are cleaned/replaced, to eliminate any carbon accumulation or sludge that could restrict the oil flow to the bearings.
- It is important to check the oil pressure and oil supply to the turbo.
- Always use new oil and new oil filters as recommended by the vehicle manufacturer when fitting a new turbo.
Overspeeding
What causes overspeeding?
- A restriction within the air intake filter, damages or split air hose, incorrect amounts of air allowed into the turbo.
- A ‘chipped’ engine that is not to standard specification.
- Tampering with the wastegate.
- Damaged or worn injectors.
- Signal loss to the SREA (Simple Rotary Electronic Actuator) for the wastegate or VNT control.
- Incorrect turbocharger fitted.
Preventing turbo failure caused by overspeeding
- Ensure there are no leaks or restrictions in the air intake.
- Ensure the wastegate or VNT linkage is operating freely.
- Make certain that the electronic sensors and ECU are operating correctly.
Keeping your vehicle in good condition by following a regular vehicle maintenance schedule to avoid expensive repairs. And remember, if you’re uncertain about how to inspect or replace a vehicle part, be sure to contact a reputable mechanic or service centre for assistance.
