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.