Chapter 10 Test

Front 1

What are the causes of a truck with no oil pressure?

Back 1

1. Check oil level

2. Leaks

3. No filter

4. Piston cooler

5. Pickup screen plugged

6. Pick up tube leaking

7. Gauge?

8. Oil pump

9. Regulator

10. Relief valve

Front 2

What are low oil pressure causes?

Back 2

1. Cracked PC

2. Too much oil

Front 3

What are the causes of high oil temperature?

Back 3

1. Low coolant

2. Belly pan full dirt

3. Oil cooler restriction

4. Low oil

5. Extreme operating conditions

6. Oil change intervals

7. Wrong oil

8. Coolant system

9. Air system

10. Fuel

Front 4

What roles does a diesel engine lubricant perform?

Back 4

A diesel engine lubricant performs a number of roles, including those of minimizing friction, supporting hydrodynamic suspension, cooling, and cleaning.

Front 5

What is viscosity?

Back 5

Viscosity describes a liquid fluid’s resistance to shear.

Front 6

What is lubricity? How does it relate to temperature?

Back 6

Lubricity describes the flow characteristics of a liquid fluid. Lubricity in engine oils is affected by temperature, with hot oils tending to flow more readily than cold oils.

Front 7

What kind of oils do diesel engine OEMs recommend? What kind is approved?

Back 7

Diesel engine OEMs recommend the use of multigrade oils over straight grades and approve the use of synthetic engine oils, especially for operation in conditions of severe cold.

Front 8

What is the pour point?

Back 8

The pour point of engine oil is the temperature at which the oil starts to gel: Oils formulated for winter use have pour point depressant additives.

Front 9

What causes sludged oil?

Back 9

Sludged oil is usually a result of oil degradation caused by prolonged low load, cold weather operation.

Front 10

What is ash?

Back 10

Ash in used engine oils is mineral residue caused by oxide and sulfate incineration. High ash levels are indicative of high-temperature operation.

Front 11

What can cause oil aeration?

Back 11

Oil aeration can be caused by high oil sump levels.

Front 12

When interpreting API oil classifications, what does GF and C denote?

Back 12

When interpreting API oil classifications, the GF prefix denotes oil formulated for gasoline fueled engines and the C denotes oil formulated for compression-ignition engines.

Front 13

Post-2007 diesel engines with EGR and DPFs are required to use what kind of engine lube?

Back 13

Post-2007 diesel engines with EGR and DPFs are required to use SAE CJ-4 rated engine lube.

Front 14

Compare synthetic oils and traditional oils. Why aren’t they extensively used?

Back 14

Most of the field research indicates that synthetic oils substantially outperform traditional oils; however, because they are more costly, they are unlikely to be extensively used by operators until engine OEMs endorse extended oil change intervals. This may not happen in a hurry due to EGR systems and the resulting contamination to the lube circuit.

Front 15

How should engine oil be taken care of and what should the technician be aware of?

Back 15

It is important to maintain the correct engine oil level, and the technician should be aware that the consequences of an excessively high oil level can be as severe as those for low sump levels.

Front 16

What types of pumps are used as oil pumps?

Back 16

Positive displacement pumps of the external gear and gerotor types are used as oil pumps in diesel engines; most are of the external gear pump design.

Front 17

How much oil is an oil pump designed to pump? What defines the peak system pressure?

Back 17

Oil pumps are designed to pump much greater volumes of oil than that required to lubricate the engine. An adjustable, pressure-regulating valve defines the peak system pressure.

Front 18

What an engine is overhauled, what should happen to the oil pump?

Back 18

When an engine is overhauled, the oil pump should be disassembled and checked for wear.

Front 19

What kind of filters are used on a heavy duty lubrication system?

Back 19

The filters used on a heavy duty lubrication system may be classified as full flow and bypass depending on how they are plumbed into the circuit.

Front 20

Where are full flow filters located? Where are bypass filters located?

Back 20

Full flow filters are located in series between the oil pump and the lubrication circuit, whereas by pass filters are arranged in parallel, receiving oil from an oil gallery and returning it directly to the oil sump.

Front 21

What should be done to filters before installation?

Back 21

Most OEMs prefer that filters be primed before installation.

Front 22

When priming a filter, what side should you fill it?

Back 22

OEMs recommend that filters be primed by filling from the inlet side only.

Front 23

How are filters usually rated?

Back 23

Filters are usually rated by their mechanical straining specification in microns but they also filter by absorption and adsorption.

Front 24

What are oil coolers? What is the cooling medium?

Back 24

Oil coolers are heat exchangers used on most heavy duty, highway diesel engines; the cooling medium used is engine coolant.

Front 25

What are the two types of oil cooler?

Back 25

There are two types of oil cooler: the bundle type and plate type.

Front 26

What does a bundle-type oil cooler consist of?

Back 26

A bundle-type oil cooler consists of a housing within which coolant is pumped through a cylindrical “bundle” of copper tubes in one direction while engine oil is pumped around the tubes flowing in the opposite direction.

Front 27

What should happen to bundle elements before assembly?

Back 27

Most OEMs prefer that bundle elements be vacuum tested for leaks before assembly; pressure testing may also be used.

Front 28

What is a benefit and drawback of plate-type oil coolers?

Back 28

Plate-type oil coolers have slightly lower cooling efficiencies but offer fewer in-service maintenance problems.

Front 29

How is engine oil pressure measurement done in most modern engines?

Back 29

Engine oil pressure measurement is, in most modern engines, performed by a variable capacitance type of sensor that signals the management computer. The dash gauge or display is therefore a computer output.

Front 30

How are electronic failure strategies triggered? What does actual oil pressure correlate with?

Back 30

Engine oil pressures usually have to fall to very low levels before programmed electronic failure strategies are triggered. Actual oil pressure correlates with rpm; for instance, a low oil pressure at idle speed represents a less serious condition than the same value oil pressure when the engine is run at rated rpm.

Front 31

What is laboratory testing in the context of engine oil?

Back 31

Laboratory testing of used engine oil samples is a relatively inexpensive method of tracking engine wear rates and providing early warning alerts to engine malfunctions. It should be adopted as part of a regular PM schedule.

Front 32

What is spectrographic testing?

Back 32

Spectrographic testing performed by laboratories tends to produce more accurate and precise assessments of the engine oil than blotter tests.

Front 33

When should routine engine oil samples be taken?

Back 33

Routine engine oil samples should be taken when the engine oil is changed, preferably at the mid-flow point when draining the sump. When extracted for diagnostic purposes, the sample should be syringed either directly from a lube gallery or from the midpoint of the sump with the engine oil at operating temperature.

Front 34

What does a high silicon reading in oil samples mean?

Back 34

When interpreting oil sample analyses, it should be noted that a high silicon reading is often an indication of a leak in the air cleaner or suction side of the air intake system.

Front 35

What SAE multigrade oils would likely be recommended by most highway diesel engine OEMs for year-round use in North America?

Back 35

15W-40

Front 36

Which of the following API classifications indicates that the oil is formulated for diesel engines meeting 2010 emissions standards?

Back 36

CJ-4

Front 37

What conditions could result from a high crankcase oil level?

Back 37

Lube oil aeration, oil pressure gauge fluctuations, and friction bearing damage

Front 38

When investigating a low oil pressure complaint, which of the following should be performed first?

Back 38

Check the crankcase oil level.

Front 39

A full flow oil filter has become completely plugged. What is the likely outcome if the engine is running?

Back 39

A bypass valve diverts the oil around the filter.

Front 40

Which of the following statements would usually correctly describe the relative temperatures of the coolant and lubricant when the engine is at operating temperature?

Back 40

Engine oil temperatures are higher than coolant temperatures.

Front 41

Which type of oil pump is most commonly used in current highway diesel engines?

Back 41

External gear

Front 42

Which of the following is usually the preferred OEM method of testing an oil cooler bundle?

Back 42

Vacuum test

Front 43

When interpreting a used engine oil analysis profile, which of the following conditions would be most likely to cause high silicon levels?

Back 43

Air cleaner perforation

Front 44

Which of the following correctly identifies the source of diesel engine oil?

Back 44

Crude petroleum

Front 45

Engine oil service classifications are standardized by which of the following organizations?

Back 45

API

Front 46

Technician A states that the operating temperature of an engine oil should be within 5°F of that of the engine coolant operating temperature. Technician B states that engine oil temperatures are probably a more accurate means of assessing actual engine operating temperature than the coolant temperature reading. Who is correct?

Back 46

Technician B only

Front 47

An auxiliary oil pump designed to feed oil to the lubrication circuit on a vehicle that operates at extreme working angles is known as a(n):

Back 47

Scavenging pump

Front 48

Oil that has a milky, clouded appearance is probably contaminated with:

Back 48

Engine coolant

Front 49

Which of the following statements best describes viscosity?

Back 49

Resistance to flow

Front 50

Technician A states that an oil cooler operates by having coolant pumped through the bundle tubes and oil circulated around the tubes. Technician B states that a leaking oil cooler core must always be replaced. Who is correct?

Back 50

Both A and B

Front 51

Technician A states that 15W-40 is the most commonly used truck engine oil. Technician B states that 15W-40 oil is not an appropriate all-season oil, because winter temperatures are often much lower than the SAE recommended ambient temperature window for this oil. Who is correct?

Back 51

Both A and B

Front 52

Technician A states that the device used to signal oil pressure values to the ECM on most electronically managed engines uses a variable capacitance operating principle. Technician B states that an oil pressure sensor usually requires a V-Ref source from the engine ECM. Who is correct?

Back 52

Both A and B

Front 53

Technician A states that an engine equipped with EGR and DPF must use API CJ-4 engine oil. Technician B states that engines manufactured before 2007 may use API CI-4 engine oil. Who is correct?

Back 53

Both A and B

Front 54

A diesel engine dash oil pressure gauge displays low and fluctuating oil pressure values when the vehicle is operated. Technician A states that this could be caused by low engine oil level. Technician B states that this could be caused by high engine oil level. Who is correct?

Back 54

Both A and B