1. Lubricating and Cooling Systems
Chapter 14
Lubricating and Cooling Systems

2. Lubrication System Holds an adequate supply of oil
Lubricates parts and reduces wear
Delivers oil to necessary areas of engine

3. Lubrication System (Cont.)
Cools and cleans components
Helps seal the engine
Removes contaminates

4. Engine Oil Formulated to lubricate and cool parts
Moving engine parts fed constant supply
Stored in oil pan or sump
Moves from sump to oil filter
Moves throughout engine via oil gallery

5. Oil Pump Pickup screen keeps large particles out of the pump
Oil pressure relief valve prevents excessive oil pressure

6. Oil Pan or Sump
Wet sump always has oil in it – most engine applications are wet sump systems
Baffles reduce sloshing

7. Dry Sump Used to eliminate oil sloshing The oil pan does not store oil
Oil reservoir is mounted remotely
Can feed oil along multiple paths at once
May have one or two oil pumps
Allows for lower engine placement

8. Oil Filter All oil leaving the pump goes to the filter
Threads onto a main oil gallery tube
Can be single disposable container or a cartridge

9. Cartridge Oil Filter

10. Oil Filter (Cont.) Some filters use an anti-drainback valve
If the filter becomes plugged, a valve opens to allow oil to bypass the filter

11. Flow Through the Oil Filter

12. Oil Coolers
Used on many diesel, high-performance, and turbocharged engines
Now common on passenger car engines
Oil flows from pump to cooler and then to the engine

13. Engine Oil Passages or Galleries

14. Dipstick Used to measure the oil level in the oil pan
Some engines do not have a dipstick
Oil level is checked by an oil sensor
Oil level is displayed on the dash

15. Oil Pressure Indicator
All vehicles have either a gauge or light
Most gauges are electronic
Warning light circuits are completed if oil pressure falls below a certain level
Some vehicles use an electronic oil level indicator to alert the driver if the level drops below a predetermined level

16. Oil Pressure Indicator (Cont.)

17. Knowledge Check Describe the flow of oil in the lubrication system.
Oil is pulled from the pan by the pump, it then flows through the filter to the crank bearings and then to the upper engine.

18. Oil Pump Inspection Mark gears before disassembly
Check gears and housing for wear
Measure gear-to-pump clearance
Inspect the pickup for sludge and debris

19. Engine Lubrication Diagnosis and Service
Oil level should be checked periodically
The oil filter is changed with the oil
Oil pump performance can be checked with an oil pressure gauge
Passages and galleries should be cleaned during an engine rebuild

20. Oil Consumption External and internal leaks
Worn piston rings allow blowby
Worn valve seals or guides

21. Oil Consumption (Cont.)
Blue smoke indicates internal leak present
External leaks occur at gaskets and seals
Oil usage increases engine wears

22. Common External Oil Leaks

23. Sludge Results from oxidation of the oil
The oil begins to solidify and form a gel
This gel cannot circulate
Can block normal oil paths
Signs include low oil pressure, increased oil consumption, increased emissions, and poor driveability

25. Sludge (Cont.) A slight amount under oil cap is normal
Sludge can be caused by:
A plugged PCV system
Extended oil change intervals
Low viscosity oils
High operating temperatures
Very lean mixtures

26. Flushing the System
Refer to the manufacturer’s service information before performing a flush
Running a solvent through the engine oil system and then draining
May help to remove sludge

27. Oil Cooler Inspect cooler and lines for leaks
Flush or replace if there is sludge buildup in the engine
Replace the cooler and clean the lines after an engine rebuild

28. Knowledge Check
What are three possible causes of oil sludge in an engine?
Lack of proper maintenance, problems with the PCV, wrong type of oil used, very high operating temperatures.

29. Cooling Systems Removes heat generated during combustion
Must allow quick engine warm up
Heat is transferred by the coolant
The coolant transfers the heat to the surrounding air

30. Cooling System Components
Thermostat
Water pump
Radiator
Radiator pressure cap
Expansion tank
Hoses
Water outlet
Water jackets
Cooling fans
Temperature indicators

31. Cooling System Components (Cont.)

32. Thermostat Controls the minimum operating temperature
Temperature sensitive flow control valve
Contains a wax pellet that expands, forcing the thermostat to open
Usually mounted on the top and front of the engine
The heat element is recessed into the block

34. Water Pump
Usually belt driven but some are driven via the cam or an electric motor
The rotating impeller circulates the coolant
The pump inlet is connected to the lower radiator hose
The pump outlet is connected to the engine block

35. Water Pump (Cont.)

36. Radiator Exchanges heat from the coolant to the surrounding air
Constructed of aluminum, brass, plastic
Radiator efficiency:
Basic design
Size of core
Amount of coolant flow through the core
Temperature of the cooling air

38. Radiator Pressure Cap Allows pressure to rise in cooling system
1 PSI of pressure increases boiling point about 3.25 degrees F (1.8 °C)
Caps normally hold between 14 – 18 PSI
Vents coolant to reservoir at specified PSI
Allows coolant back into engine when cool

39. Radiator Cap
Pressure operation
Vacuum operation

40. Expansion Tank
Designed to catch and hold coolant passing from radiator cap as the coolant expands

41. Hoses Made of butyl or neoprene rubber
Cushion engine vibrations and movement
Most vehicles have at least four hoses while some have five
Upper and lower radiator hoses
Heater hoses
Bypass hose

42. Knowledge Check
What is the purpose in allowing pressure to increase in the cooling system?
Increasing pressure raises the boiling point of the coolant.

43. Water Outlet Connects the engine and upper radiator hose
Also called a gooseneck, elbow, inlet, outlet, or thermostat housing
May cover thermostat

44. Water Jackets Surround combustion chambers
Some engines use plastic inserts to direct coolant flow within the jacket
Includes core plugs and block drain

45. Water Jackets

46. Hose Clamps
Designed to apply consistent clamping pressure

47. Belt Drives Used to drive the water pump and other accessories
Must be in good condition and properly tensioned

48. Heater System
Hot liquid passenger compartment heater is part of the cooling system
Air is directed over the heater core and can be mixed with outside air

50. Cooling Fans
Cooling system efficiency depends on the amount of heat that can be removed
At high speeds ram air is sufficient
At low speeds an idle air is delivered by a fan
Mounted very close to the radiator

51. Electric Cooling Fans Replaced most belt driven fans
Controlled by a temperature switch and/or air conditioner switch via the PCM

52. Belt Driven Fans May be flex-blade design
Fan clutches uncouple the fan when not needed
Temperature sensitive clutch
RPM sensitive clutch

54. Hydraulic Fans Some vehicles use power steering fluid to drive the fan
Fluid is routed into the fan drive based on cooling requirements

55. Temperature Sensors
Sends signal to PCM for cooling fans

56. Temperature Indicator
Alerts the driver of an overheating condition
Threaded into a water jacket
May also supply information to the
on-board computers

57. Knowledge Check What are three types of cooling fans?
Electric, belt-driven, and hydraulic.

58. Cooling System Diagnosis
Testing for electrolysis in cooling systems
Current passing through the water separates hydrogen and oxygen
Removes the protective layer inside of radiator tubes
Caused by improper electrical system grounding

59. Inspection of Cooling System
Most common problem is overheating
Can be caused by the inability to absorb, transport, or dissipate heat
Confirm if engine is overheating
Use a temperature probe at radiator inlet tank

60. Effects of Overheating
Detonation
Preignition
Blown head gasket
OHC cam seizure
Blown hoses
Radiator leaks
Cylinder damage due to swelled pistons
Sticky exhaust valve stems
Engine bearing damage

61. Temperature Test Allows monitoring of temperature changes
Thermostat opening temperature can be checked from a cold start
Probe for cool spots in the radiator
Cooling fan switch operation can be monitored

62. Radiator Checks Cold spots indicate internal restrictions
Inspect for external restrictions and leaks
Check for loose cooling fins
Salt and road debris can corrode fins and tubes

63. Checking Hoses Hoses deteriorate from the inside
Upper radiator hose suffers the most
Check lower hose reinforcement spring

64. Checking Fans and Fan Clutches
Inspect fan shroud for fit and damage
Damage to belt driven fan can damage water pump and/or radiator
Check fan clutches for oil loss
Replace clutch if it spins with little or no resistance with the engine off

65. Electric Cooling Fans Check fan, blades, and mounting assembly
Fan should energize with A/C on and once engine reaches operating temperature
If the fan does not come on, jumper the fan motor to the battery
Follow the service procedures given by the manufacturer

66. Testing the Thermostat
Should be closed when cold
Opens when hot
Most are fully open at 195° F (90.5 °C)

67. Water Pump Checks Noise and leakage are common problems
Common causes of water pump bearing failure:
A bent fan
A missing piece of fan blade
A cracked fan blade
Fan mounting surfaces that are not flush
A worn fan clutch

68. Testing for Leaks
Most common cause of overheating is low coolant levels due to leaks
Hoses, radiator, heater core, water pump, thermostat housing, freeze plugs, transmission oil cooler, head gaskets, and intake gaskets are common leakage points

69. Leak Detection with Dye
Pour dye into cooling system
Run engine to operating temperature
With engine off, inspect with a black light

70. Combustion Leak Check
Internal leak may be present when there are no visible external leaks but engine is losing coolant or hold pressure
Typically caused by cracked head, head gasket, or warped head

71. Testing the Radiator Cap
Leaking cap will reduce boiling point and cause an overheating condition

72. Water Outlet Can fail from internal corrosion
Improper torquing can warp or break outlet

73. Knowledge Check
Describe how to perform a cooling system leak inspection.
Check and top off the coolant, install a pressure tester, pressurize the system no more than indicated on the radiator cap, check for leaks.

74. Cooling System Service
Pressure test the system for leaks
Check coolant condition and strength using a hydrometer
Check radiator cap for proper pressure
Test thermostat for proper opening and closing temperatures

75. Cooling System Service (Cont.)
Check hoses for leaks and swelling
Check the system with a voltmeter for electrochemical degradation
Check water pump for bearing failure and leaks
Check cooling fans and fan clutch for proper operation

76. Cooling System Service (Cont.)
Drain coolant below level of hose being replaced
Cut end of old hose
Clean neck of hose fitting
Dip ends of hose in coolant when installing
Do not reuse spring clamps
Install and tighten hose clamps

77. Correct Hose Clamp Installation

78. Hose Clamps Worn drive clamps often replace spring clamps
Thermoplastic clamps are shrink fit with a heat gun
Readjust a new clamp after a brief run-in period

79. Thermostat Always replace with same temperature
Replace the gasket or seal at same time

80. Repairing Radiators
Repairs depend on radiator construction and the type of damage
Most repairs are made by specialty shops
Plastic tanks are replaced, not repaired

81. Replacing the Water Pump
Drain the cooling system
Remove parts that interfere with removal
Loosen bolts in a crisscross pattern from the center outward
Follow the procedures given by the manufacturer

82. Draining the Coolant Coolant should be changed every two to four years
Drain reservoir and cooling system
Never pour coolant into a sewer or onto the ground.

83. Flushing the Cooling System
Flush the system when coolant is changed and when a water pump is replaced
Power flushing, back flushing, and coolant exchanges force old coolant out and new coolant in
Before using any flush chemical, check to make sure it is safe for the system

84. Refilling and Bleeding
Refill with correct type
Determine the total capacity
Refill system and run engine to operating temperature
Remove air trapped in the system
Refill and recheck coolant level and for any leaks

85. Refilling and Bleeding (Cont.)
Some engines have air bleed valves in cooling system
Open valves when refilling system
Once coolant comes out of the valve, close the valve

86. Refilling and Bleeding (Cont.)
Many shops use a vacuum fill tool
Vacuum is pulled on cooling system
Vacuum draws the new coolant in and eliminates air pockets

87. Special Procedures for Hybrid Vehicles
Require special coolants for engine and inverter
Some models use hot coolant storage tanks
Coolant in the radiator could be cold but hot in the storage tank
Follow all manufacturer service and safety procedures

88. Coolant Exchangers
Removes old coolant and replaces it with new coolant
May be air or battery powered
Normally performed with the engine off
Flush out coolant before using on next vehicle if it requires a different coolant

89. Knowledge Check
Technician A says hybrid vehicles may require special cooling system service procedures. Technician B says a hybrid vehicle may require a special coolant for the hybrid system. Who is correct?
Both A and B