Top 4 Common Turbo Problems

#1 OIL STARVATION

Lack of/not enough oil flowing to the turbo and its bearing system. It causes the turbo to work while under-lubricated.

OUTCOME:

Turbo’s shaft and bearing seizure. Shaft breakage.

HOW TO IDENTIFY?

Turbo does not operate – engine failure.

POSSIBLE CAUSES:

• Oil pressure at the turbo inlet is too low Oil pump issues, lack of oil

• Oil feed line blockage: inner flow restrictions caused by oil sludging, coking, or impurities

• Oil leaks and general engine lubrication system failures

• Impaired oil characteristics – e.g., oil sludging, worn oil, cooking, shutting off the too-hot turbo

#2 OIL COKING

Oil lubricative characteristics are impaired by excessive exhaust temperatures and hardened oil particle formation – oil coking/carbonizing.

OUTCOME:

Oil sludging and coking, causing the turbo’s shaft and bearing to work as under-lubricated, leading ultimately to a complete breakdown. Oil distribution channels suffer from severe clogs and flow restrictions.

HOW TO IDENTIFY?

Worsening/limited turbo efficiency leads to a complete failure, including shaft/bearings seizure – turbo does not operate – and engine failure.

POSSIBLE CAUSES:

• Too high temperature of the exhaust gases. The problem may have the root cause in improper combustion and exhaust system issues. Faulty operation of the exhaust sensors, filtering system (DPF) failures, fuel injection system failures (improper fuel dosing), air intake system and/or MAP, and MAF sensor failures are why the exhaust temperatures rise excessively and affect the turbo.

• General engine lubrication problems

#3 INTERNAL LEAKS

Oil leaks from the turbo’s blown internal oil seals and piston rings. The leaking oil gets into the engine’s intake and exhaust system.

OUTCOME:

Excessive oil leaks inside the turbo, both into the turbine and the compressor side. Severe contamination of VNT/WG mechanisms of the turbo. Excessive oil consumption by the engine. Consequential damages to the exhaust treatment devices and the engine.

HOW TO IDENTIFY?

Turbo contaminated by oil, oil smell in the cabin, the engine burns oil – vehicle smoking blue/grey, improper engine idling (revs increase), severe engine failures including burst by so- called ‘run-away-engine’.

POSSIBLE CAUSES:

• Oil overpressure inside the turbo: Flow restrictions in the oil return line of the turbo or engine breather issues

• Too high pressure in the oil feed line

• Overpressure on the turbine side of the turbo (exhaust line)

#4 OIL DEGRADATION

Impaired turbo lubrication by excessive oil wear, oil Impaired lubrication ability, and oil contamination, including carbon, soot, and sludge built up in the oil, lead to severe damage to critical turbo components – mainly the shaft and the bearing system.

OUTCOME:

Under-lubrication of the turbo shaft and bearing. The resulting abrasion led to reduced turbo efficiency and, ultimately, to complete shaft breakage and turbo failure.

HOW TO IDENTIFY?

Turbo does not operate – engine failure.

POSSIBLE CAUSES:

• Impaired lubrication – excessive oil wear caused by high mileage and extended oil change intervals.

• Oil contamination caused by lubricant filtration problems and general oil distribution system failures. Oil sludge formation, coking/carbonizing.

Nissens has an extensive library of technical information at https://support.nissens.com/en/experts, including insights into the system’s essential procedures, maintenance, troubleshooting, and component installation, as well as thermal management systems

of electric & hybrid vehicles. Training materials and courses can be found at https://showroom.nissens.com/ntc/