Lubrication System Fundamentals
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Transcript of Lubrication System Fundamentals
Subject: Automotive Technology
Topic: Lubrication System Fundamentals
Date: 13 April 2015
Subtopic: Lubrication System Functions
Cooling System repair
Overheating and Overcooling
Cooling system Instrumentation
Grade 9
Time: 20hrs.
General objectives: To explain the function operation and construction of the lubrication system as well as to list and explain the major components, and discuss causes and effects of “Low oil pressure” and “High oil pressure” of the lubrication system.
Specific Objectives:
State the Lubrication system function
List the main parts of the lubrication system
Explain the purpose of the main parts of the lubrication system
Explain the operation of the lubrication system
Previous Knowledge: Heat transfer through the mediums solid, liquid, and gas. Understanding of
frictional force.
Teaching Points:
Lubrication system function.
A lubrication system must to carry out the duty of operating temperature between 82°C - 96°C.
Since heated metal parts of the engine expands, maintaining correct temperature ensures
correct clearances, proper combustion, minimum emissions and better performance. To quickly
reach operating temperature is also a priority of the cooling system.
Major components of the cooling system
Radiator
Radiator cap
Radiator fan
Radiator top and bottom hose
Thermostat
Water pump
Bypass pipe
Bypass hose
Thermostat switch (fan)
Temperature sensor
Temperature switch (gauge)
Heater core
Heater core hoses
Coolant recovery reservoir
Overflow hose
Water Impeller Pump
Coolant is thrown outward by centrifugal force, producing suction in the center of the pump housing.
Coolant Flow
Coolant flows out of the radiator, through the lower hose, into the engine
It then flows through the pump, around the cylinders, through the heads, up through the
thermostat, and back into the radiator
Radiator hoses
carry coolant between the engine water jackets and the radiator
lower hose is exposed to water pump suction so a spring may prevent collapse
Heater hoses
carry hot coolant to the heater core
smaller diameter than radiator hoses
Radiator
The radiator absorbs the heat from the coolant, and transfers it to the outside air.
Types of Radiator
Radiator Cap
Radiator Cap Pressure valve
Spring-loaded disk
Normally, water boils at 212 ºF (100 ºC)
For each pound of pressure increase, boiling point goes up about 3 ºF (1.6 ºC)
Typical pressure:
12–16 psi
raises boiling point to
250–260 ºF (121–127 ºC)
Radiator Cap Vacuum Valve
Opens to allow flow back into the radiator when the coolant temperature drops
Closed and Open Cooling Systems
Closed cooling system
uses an expansion tank
overflow tube is routed into reservoir tank
Open cooling system
allows excess coolant to leak onto the ground
Pressure Cap Operation
Hot engine
Pressure Cap Operation
Cold engine
Cooling System Fan
Pull air through the core of the radiator
Increase volume of air through the radiator
Driven by fan belt or electric motor
Thermostat
Senses coolant temperature and controls coolant flow through the radiator
Reduces coolant flow on cold engine
Increases coolant flow on hot engine
Thermostat Operation
Cold engine
wax-filled pellet has contracted
spring holds valve closed
Hot engine
when heated, pellet expands
spring tension is overcome
valve opens
Evaluation: I:
Students will answer the following questions to show their understanding of the concepts
1. Which of the following is a function of the engine's lubrication system?A.
Holds an adequate supply of oil
B.
Removes contaminates from the oil
C.
Delivers oil to all necessary areas of the engine
D.All of the above
2. Technician A says that the 'S' service rating system (SA,SB,SC,etc.) rates oil for gasoline engines and refers to the level of additives and other characteristics of the oil's makeup. Technician B says that an SL rated oil can be used in place of an SH rated oil. Who is correct?
A.A onlyB B only
.C.Both A and
BD.Neither A nor B
3. Engine oil viscosity ratings are being discussed. Technician A says a low-weight oil works best in high-temperature regions. Technician B says all multi-viscosity oils are interchangeable. Who is correct?
A.A onlyB.
B only
C.Both A and B
D.Neither A nor B
4. Technician A says that engine oil is used to clean, cool, and lubricate the engine. Technician B says engine oil helps seal some internal engine parts. Who is correct?
A.A onlyB.
B only
C.Both A and B
D.Neither A nor B
5. Engine oil pressure is being discussed. Technician A says low pressure may be caused by worn engine bearings. Technician B says oil viscosity, temperature, and contamination can affect oil pressure. Who is correct?
A.A onlyB.
B only
C.Both A and B
D.Neither A nor B
6. When an engine experiences decreased oil pressure, Technician A says that piston slap is a likely initial symptom. Technician B says that valvetrain noise is common with decreased oil pressure. Who is correct?
A.A onl;yB.
B only
C.Both A and B
D.Neither A nor B
7. Which of the following would not cause low oil pressure?A.
Plugged oil pickup screen
B.
Excessive oil dilution
C.
Excessive engine valve lifter wear
D.
Excessive engine bearing wear
8. Which of the following would be a likely cause excessive oil consumption?A.
Faulty PCV system
B.Worn piston ringsC.
Neither A nor B
D.
Both A and B
9. Technician A says high oil pressure wil cause valve cover gasket leaks. Technician B says low oil pressure can be caused by a faulty PCV system. Who is correct?
A.A onlyB.
B only
C.Both A and B
D.Neither A nor B
10. Technician A says that extended life coolant is more environmentaly friendly. Technician B says two year coolant (green) can be used to top off all automotive cooling systems. Who is correct?
A.A onlyB.
B only
C.Both A and B
D.Neither A nor B
11. In most automotive applications, the water pump is driven by the:A.FlywheelB.
Camshaft
C.Crankshaft
D.
Impeller
12. Why are modern cooling systems pressurized?A.To raise coolant's boiling pointB.
To prevent leaks
C.To move the coolant through the systemD.To prevent corrosion in the system
13. What is the most likely symptom of a vehicle with a non-operational electric cooling fan?A.Overheating at highway speedsB.Overheating at low speedsC.Overheating at all speedsD.Lack of heat from the heater core
14. The typical recommended mixture of water and antifreeze to form engine coolant is:A.
30/70
B.50/50C.
40/60
D.60/40
15. Most manufacturers recommend that cooling systems with conventional (green) antifreeze should be drained, flushed, and filled every:
A.Six monthsB.YearlyC.
Two years
D.
Five years
16. When pressure testing a cooling system, the pressure applied should be:A.
Pumped up as high as possible
B.
Pumped up to the pressure cap rating
C.Pumped up to 10 psi
D.Released quickly17. Technician a says a leaking head gasket could explain the presence of coolant in the
eingine's crankcase. Technician B says that coolant that is a milky brown color has been contaminated with either engine or automatic transmission oil. Who is correct?
A.A onlyB.
B only
C.Both A and B
D.Neither A nor B
18. Technician A says an electric cooling fan may come on without the ignition being turned on. Technician B says an electric cooling fan may be controlled by the engine control computer. Who is correct?
A.A onlyB.
B only
C.Both A and B
D.Neither A nor B
19. What is a likely harmful effect of engine overheating?A.
Damage to combustion chamber parts
B.Damage in the crankcaseC.Poor gas mileageD.
High tailpipe emissions
20. What is a likely harmful effect of engine underheating?A.
High tailpipe emissions
B.
Sludge buildup in the oil
C.Poor gas mileageD.All of the
above
Evaluation: II:
Out of a total of four specific objectives, three were satisfied at the end of the lesson.
Over 80% of the students understood the basic variable and conditions that makes a
cooling system function to keep the engine at optimum temperature.
Most students had a basic working knowledge of a cooling system before the start of
the lesson. The theory of cooling system and transfer of heat was partially familiar to
99% of the students, and so was easily grasped due to simple and well-chosen teaching
references.
For the next lesson we will continue with the “Basic engine operation”. Some seating
changes may need to be made as a few boys at the rear of the classroom are spending
most of the time talking during the lesson.