Exam 51: Failure Analysis

When performing failure analysis on engine components, the technician is required to have an understanding of which of the following?

When evidence of lacquering is found on a set of crankshaft main bearings, which of the following operating and maintenance practices should be examined first?

You are determining the root cause of an older DPF that has failed because it emits continual black smoke under load but has logged no fault codes. Technician A says the seals in the turbocharger could be leaking and should be inspected. Technician B says that this can be caused by abnormally high engine temperatures so the cooling system should be checked. Who is correct?

What type of damage can result to an EUI when fuel supply pressures fall below specification?

Which of the following must be located during failure analysis investigation if a repeat is to be avoided?

If a dry sleeve designed for a 0.0015 inch (0.038 mm) loose fit is installed to the engine block with insufficient clearance, which of the following will more likely result?

You are inspecting a crankshaft fracture in which the fracture faces appear relatively smooth with evidence of beach marks. What type of fracture would be the likely diagnosis?

Technician A says that the most common cause of EHI and EUI terminal post failures is overtorquing of the fasteners. Technician B says that at least one OEM permits EUI cartridge replacement in the event of a failure. Who is correct??

Technician A says that most corrosion deterioration on engine metals is related to acids in degraded engine lube. Technician B says that most corrosion wear on engine components is either directly or indirectly related to oxidation. Who is correct?

Technician A says that when a component fails due to a metallurgical defect, the technician is at fault. Technician B says that a casting inclusion in a cylinder head can be classified as a metallurgical defect. Who is correct?

Technician A says that a keyway cut into a shaft is a potential stress raiser. Technician B says that oil holes in crankshafts are potential stress raisers. Who is correct?

?What does Bosch research indicate is the number one reason for EHI failures?

An engine is disassembled because of a single torched piston: the other five appear normal. Which of the following should be investigated first?

When performing failure analysis on an EGR-aspirated diesel engine with soot build-up in the intake manifold, which of the following should you check first?

When it is determined that a crankshaft has a torsional failure, all of the following should be balance-checked EXCEPT:

Technician A says that a high percentage of EUI internal leakage problems can be related to contaminated fuel. Technician B says that internal leakage is the most common cause of EUI failures. Who is correct?

When adhesive wear occurs on crankshaft main bearing, which of the following would be the more likely cause?

When a piston fails due to cracks in the cavity edge of the Mexican hat recess, the usual cause would be:

When a set of wet liners has evidence of severe cavitation, which of the following maintenance and operating practices should be investigated first?

Technician A says that visual inspection is one of the most important factors of good failure analysis practice. Technician B says that laboratory analysis is usually required to accurately pinpoint root cause. Who is correct?