Question 1

Technician A says that a diesel engine that is operated continuously under light and idle loads, can be classified as severe service operation. Technician B says that a diesel engine hauling cargo in a routine linehaul operation can be classified as severe service operation. Who is correct?
A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Accepted Answer

Technician A is correct because operating a diesel engine continuously under light and idle loads can lead to issues such as incomplete combustion and soot buildup, which are characteristics of severe service operation. Technician B is incorrect because routine linehaul operation, which involves consistent and possibly heavy hauling, does not necessarily classify as severe service operation, as these engines are designed for such use.

Question 2

What is a synthetic oil likely to achieve when compared to a petroleum base diesel engine oil?
A) resistance to breakdown
B) better tolerance to extreme temperatures
C) extended service life
D) all of the above

Accepted Answer

Synthetic oils are engineered to provide superior performance compared to conventional petroleum-based oils. They offer better resistance to breakdown, can tolerate more extreme temperatures without losing viscosity, and generally allow for longer intervals between oil changes, thereby extending the service life of the engine.

Question 3

Technician A says that high detergent oils aerate more easily. Technician B says that high detergent oils should be used in engines equipped with a HEUI fuel system. Who is correct?
A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Accepted Answer

The answer of Technician A says that high detergent oils...

Question 4

When does an EG- to- water mix maximize its antifreeze protection?
A) 100% EG
B) 60:40 EG to water mix
C) 50:50 mix
D) 40:60 EG to water mix

Accepted Answer

The answer of When does an EG- to- water mix...

Question 5

When does a PG mix maximize its antifreeze protection?
A) 100% PG
B) 60:40 PG to water mix
C) 50:50 mix
D) 40:60 PG to water mix

Accepted Answer

100% PG provides the maximum antifreeze protection because it has the highest concentration of PG, which is the antifreeze agent.

Question 6

Which type of diesel engine coolant is said to be able to last for the life of the engine?
A) EG
B) PG
C) ELC
D) WEC

Accepted Answer

The answer of Which type of diesel engine coolant is...

Question 7

Technician A says that most OEMs recommend priming oil filters prior to installation. Technician B says that some current diesel engines incorporate an integral oil priming circuit. Who is right?
A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Accepted Answer

Most OEMs do recommend priming oil filters prior to installation to prevent dry starts and ensure immediate oil pressure upon engine start-up. Additionally, some modern diesel engines do have an integral oil priming circuit designed to automatically prime the engine oil system, reducing wear and tear during startup.

Question 8

If a diesel engine is equipped with a diesel particulate filter (DPF) which of the following lube oil classifications must NOT be used?
A) FA-4
B) CK-4
C) CJ-4
D) GI-4

Accepted Answer

GI-4 is not a recognized API service category for diesel engines. The correct categories for modern diesel engines, especially those equipped with DPFs, are CJ-4, CK-4, and FA-4. These classifications ensure the oil is compatible with the emissions control systems and will not damage the DPF.

Question 9

Technician A says that filling an oil filter with clean engine oil prior to installation constitutes priming it. Technician B says when oil filters are installed dry on engines equipped with an oil priming circuit, it is good practice to seal the gasket with silicone. Who is correct?
A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Accepted Answer

Filling an oil filter with clean engine oil before installation does indeed prime it, ensuring immediate lubrication upon engine start. However, using silicone on the oil filter gasket is not recommended; instead, a light coating of oil is advised to ensure a proper seal.

Question 10

Technician A says that the type of antifreeze can always be determined by its color. Technician B says that both PG and EG should be mixed with distilled water in order to maximize its service life. Who is correct?
A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Accepted Answer

Technician B is correct because both Propylene Glycol (PG) and Ethylene Glycol (EG) antifreezes should be mixed with distilled water to prevent mineral deposits and maximize service life. Technician A is incorrect because antifreeze color is not a reliable indicator of its type, as different manufacturers may use different colors for the same type of antifreeze.

Question 11

After opening a container of premix ELC, what is the maximum amount time it should be left before installing into a cooling system?
A) one hour
B) one week
C) one month
D) one year

Accepted Answer

Premix ELC (Extended Life Coolant) should be installed into a cooling system within one week after opening to ensure its effectiveness and prevent contamination.

Question 12

What is the recommended procedure when preparing an EG and distilled water coolant for installation into an engine?
A) pour distilled water in radiator first followed by EG concentrate
B) pour EG in radiator first followed by distilled water
C) alternate EG and distilled water into radiator one quart at a time
D) mix EG and distilled water outside the radiator: pour into radiator as a mixture

Accepted Answer

Mixing ethylene glycol (EG) and distilled water outside the radiator ensures a uniform coolant mixture before it is poured into the radiator. This method helps in achieving the correct concentration and prevents layering or uneven distribution of the coolant components.

Question 13

Technician A says that diesel fuel can be safely pumped at rates of up to 20 gallons per minute at a refueling station. Technician B says that a portable diesel fuel container must be lined with zinc to prevent degradation. Who is correct?
A) Technician A
B) Technician B
C) Both A and B
D) Neither A nor B

Accepted Answer

Diesel fuel can indeed be safely pumped at rates of up to 20 gallons per minute at a refueling station, which is a standard practice to accommodate the larger fuel tanks of diesel vehicles. However, there is no requirement for portable diesel fuel containers to be lined with zinc to prevent degradation. Diesel fuel storage requirements focus on preventing leaks and spills rather than on the specific materials used for the container's interior lining.

Question 14

Technician A says that it is good practice to refuel a diesel fueled truck with the engine running in cold weather. Technician B says that some modern diesel fuel systems may be under moderate pressure so care must be taken when removing the fill cap. Who is correct?
A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Accepted Answer

Technician B is correct because modern diesel fuel systems can indeed be under pressure, and caution is necessary when removing the fill cap to avoid injury or damage. Refueling with the engine running, especially in cold weather, is generally not recommended due to safety concerns, making Technician A's statement incorrect.

Question 15

After servicing and priming a diesel engine fuel system, what is the maximum duration cranking time permitted before resting?
A) 30 seconds
B) 1 minute
C) 2 minutes
D) until the batteries die

Accepted Answer

The maximum duration for cranking a diesel engine after servicing and priming the fuel system is 30 seconds, followed by a rest period to prevent overheating and damage to the starter motor.

Question 16

What is the maximum amount of time biodiesel should be retained in a diesel engine fuel tank?
A) one week
B) one month
C) 6 months
D) 1 year

Accepted Answer

The answer of What is the maximum amount of time...

Question 17

When draining collected water from the sump of a fuel/water separator, which of the following is recommended?
A) turn off the engine
B) completely drain the separator
C) recycle the drain-off into the fuel tank
D) drain the secondary filter

Accepted Answer

Turning off the engine is recommended when draining collected water from the sump of a fuel/water separator to prevent air from entering the fuel system and to ensure safety during the maintenance process.

Question 18

What is the usual OEM recommendation when installing secondary fuel filters?
A) fill with clean diesel fuel
B) install dry, then prime the fuel system
C) install dry and use ether to start engine
D) install dry, then crank until the engine fires

Accepted Answer

Installing secondary fuel filters dry and then priming the fuel system is typically recommended by OEMs to avoid introducing contaminants into the fuel system and to ensure proper fuel flow and pressure.

Question 19

Technician A says that when a DPF is regenerated, any accumulated ash is burned off. Technician B says that when a DPF is regenerated, entrapped soot is burned off. Who is correct?
A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Accepted Answer

During a DPF (Diesel Particulate Filter) regeneration, entrapped soot is burned off, not ash. Ash, which is a byproduct of combustion and cannot be burned off, accumulates over time and must be physically removed.

Quiz 14: Servicing and Maintenance

Technician A says that a diesel engine that is operated continuously under light and idle loads, can be classified as severe service operation. Technician B says that a diesel engine hauling cargo in a routine linehaul operation can be classified as severe service operation. Who is correct?

What is a synthetic oil likely to achieve when compared to a petroleum base diesel engine oil?

Technician A says that high detergent oils aerate more easily. Technician B says that high detergent oils should be used in engines equipped with a HEUI fuel system. Who is correct?

When does an EG- to- water mix maximize its antifreeze protection?

When does a PG mix maximize its antifreeze protection?

Which type of diesel engine coolant is said to be able to last for the life of the engine?

Technician A says that most OEMs recommend priming oil filters prior to installation. Technician B says that some current diesel engines incorporate an integral oil priming circuit. Who is right?

If a diesel engine is equipped with a diesel particulate filter (DPF) which of the following lube oil classifications must NOT be used?

Technician A says that filling an oil filter with clean engine oil prior to installation constitutes priming it. Technician B says when oil filters are installed dry on engines equipped with an oil priming circuit, it is good practice to seal the gasket with silicone. Who is correct?

Technician A says that the type of antifreeze can always be determined by its color. Technician B says that both PG and EG should be mixed with distilled water in order to maximize its service life. Who is correct?

After opening a container of premix ELC, what is the maximum amount time it should be left before installing into a cooling system?

What is the recommended procedure when preparing an EG and distilled water coolant for installation into an engine?

Technician A says that diesel fuel can be safely pumped at rates of up to 20 gallons per minute at a refueling station. Technician B says that a portable diesel fuel container must be lined with zinc to prevent degradation. Who is correct?

Technician A says that it is good practice to refuel a diesel fueled truck with the engine running in cold weather. Technician B says that some modern diesel fuel systems may be under moderate pressure so care must be taken when removing the fill cap. Who is correct?

After servicing and priming a diesel engine fuel system, what is the maximum duration cranking time permitted before resting?

What is the maximum amount of time biodiesel should be retained in a diesel engine fuel tank?

When draining collected water from the sump of a fuel/water separator, which of the following is recommended?

What is the usual OEM recommendation when installing secondary fuel filters?

Technician A says that when a DPF is regenerated, any accumulated ash is burned off. Technician B says that when a DPF is regenerated, entrapped soot is burned off. Who is correct?