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Chapter 14

Chapter 14. Lubricating and Cooling Systems. Lubrication System. Holds an adequate supply of oil Lubricates parts and reduces wear Delivers oil to necessary areas of engine. Lubrication System (Cont.). Cools and cleans components Helps seal the engine Removes contaminates. Engine Oil.

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Chapter 14

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  1. 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.

  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 LubricationDiagnosis 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

  24. 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

  25. 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

  26. 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

  27. Knowledge Check • What are three possible causes of oil sludge in an engine?

  28. 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

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

  30. Cooling System Components (Cont.)

  31. 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

  32. 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

  33. Water Pump (Cont.)

  34. 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

  35. 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

  36. Radiator Cap Pressure operation Vacuum operation

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

  38. 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

  39. Knowledge Check • What is the purpose in allowing pressure to increase in the cooling system?

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

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

  42. Water Jackets

  43. Hose Clamps • Designed to apply consistent clamping pressure

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

  45. 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

  46. 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

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