Cooling System Basics
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Questions and Answers

What should be inspected if a turbo screen and exhaust manifold show signs of dried corrosion inhibitor?

  • Exhaust port for cracks or dried coolant (correct)
  • Coolant level in the expansion tank
  • Air intake for blockages
  • Oil leaks in the engine

    • What pressure is applied during a hydro-test after refilling the engine with hot water?

  • 10psi
  • 30psi
  • 25psi (correct)
  • 20psi

    • If water is seen running down the exhaust port but no source is identified, what should be done next?

  • Conduct a 90psi block test
  • Inspect the engine top plate directly
  • Remove the exhaust manifold section for that cylinder (correct)
  • Replace the entire exhaust manifold

    • When is it necessary to apply a 90psi block test to an engine block?

    <p>After conducting cold and hot hydro-tests with no leaks</p> Signup and view all the answers

    What is the first step suggested when checking an engine experiencing high coolant temperature?

    <p>Check the coolant level in the expansion tank</p> Signup and view all the answers

    What component is responsible for drawing coolant from the expansion tank?

    <p>Aspirator</p> Signup and view all the answers

    What is the primary function of the centrifugal water pumps in the engine cooling system?

    <p>To circulate cooling water</p> Signup and view all the answers

    What do the pump outlet elbows connect to in the cooling system?

    <p>Water inlet manifolds</p> Signup and view all the answers

    How is coolant supplied to each cylinder liner?

    <p>Via a water inlet tube assembly</p> Signup and view all the answers

    What component prevents direct impingement of water on the inner liner wall?

    <p>Deflector</p> Signup and view all the answers

    What does the engine cooling system primarily consist of?

    <p>Water pumps, manifolds, and outlet manifolds</p> Signup and view all the answers

    What indicates that low water levels are detected in the cooling system?

    <p>Low water detect indicator</p> Signup and view all the answers

    What is the main purpose of the four pass aftercooler developed by EMD in partnership with Young Radiator?

    <p>To provide a more efficient coolant recycling process</p> Signup and view all the answers

    How do electrically driven cooling fans contribute to the coolant management system?

    <p>They move air through radiators to cool the coolant.</p> Signup and view all the answers

    What feature helps control the water temperature in the coolant management system?

    <p>Temperature switches</p> Signup and view all the answers

    What happens to the coolant when the engine is first started?

    <p>It is drawn from the expansion tank.</p> Signup and view all the answers

    What role do temperature sensors play in newer cooling systems?

    <p>They handle fan and shutter control via a microprocessor.</p> Signup and view all the answers

    Where does coolant go after it absorbs heat from the lube oil?

    <p>Back to the aftercoolers</p> Signup and view all the answers

    Why is an airbox temperature imbalance a concern in engine design?

    <p>It can affect engine performance and efficiency.</p> Signup and view all the answers

    What is the function of the 'Y' pipe in the coolant system?

    <p>To direct water out to the radiator assemblies</p> Signup and view all the answers

    What contributes to achieving a consistent coolant flow pattern between engine banks?

    <p>Implementing four connection flanges on the cores</p> Signup and view all the answers

    What is one of the basic requirements for coolant in EMD engines?

    <p>Must not form scale or sludge deposits</p> Signup and view all the answers

    Which type of corrosion inhibitor is primarily used for EMD engines?

    <p>Borate-nitrate type inhibitors</p> Signup and view all the answers

    What should be done with powder and pellet form inhibitors before adding them to the cooling system?

    <p>They should be dissolved in water first</p> Signup and view all the answers

    Why is water containing excessive solids unsuitable for EMD engine cooling systems?

    <p>It can cause corrosion and scale build-up</p> Signup and view all the answers

    What should the concentration of borate-nitrate inhibitors be maintained above in EMD engines?

    <p>5625 parts per million</p> Signup and view all the answers

    What is the main function of coolant in EMD engines?

    <p>To transfer heat from engine components to radiators</p> Signup and view all the answers

    What processing methods can be used to make unsuitable water suitable for EMD engine cooling systems?

    <p>Softening, de-ionizing, or distillation</p> Signup and view all the answers

    What is a key consideration when selecting a coolant for EMD engines?

    <p>It must not deteriorate seals or gaskets</p> Signup and view all the answers

    Why is it important to analyze coolant samples regularly?

    <p>To check for proper solution of corrosion inhibitor</p> Signup and view all the answers

    What can contribute to the deterioration of water quality for use in cooling systems?

    <p>Presence of hardness salts and chlorides</p> Signup and view all the answers

    What type of pump is used in EMD engines for cooling water?

    <p>Self-draining centrifugal pump</p> Signup and view all the answers

    Which component supports the pump drive shaft in EMD engine water pumps?

    <p>Sealed grease lubricated ball bearings</p> Signup and view all the answers

    What is the maintenance requirement for the bearings in the water pump?

    <p>No maintenance required</p> Signup and view all the answers

    What is the orientation of the water pump's rotation relative to the engine crankshaft?

    <p>Opposite direction</p> Signup and view all the answers

    Where can specifications for antifreeze usage in EMD engines be found?

    <p>M.I. 1748</p> Signup and view all the answers

    How many water pumps are present on an EMD engine with eight cylinders?

    <p>One</p> Signup and view all the answers

    Which of the following components is not part of the water pump assembly?

    <p>Cylinder head</p> Signup and view all the answers

    What type of lubrication do the bearings in the EMD water pump utilize?

    <p>Grease lubrication</p> Signup and view all the answers

    Which of the following statements about the EMD engine water pump is true?

    <p>It has a sealed bearing system.</p> Signup and view all the answers

    What ensures the water pumps are self-draining?

    <p>Gravity design</p> Signup and view all the answers

    What should be checked for defects along the entire length of the engine?

    <p>Water manifolds</p> Signup and view all the answers

    What action is taken when the oil level drops below the cooler inlet line?

    <p>Drain the lube oil strainer housing</p> Signup and view all the answers

    What component should be checked for leaks in turbo engines?

    <p>Aftercooler cores</p> Signup and view all the answers

    What specific condition indicates a potential issue with the lube oil cooler?

    <p>Water running down from the lube oil cooler</p> Signup and view all the answers

    What should be regularly inspected to ensure proper engine function?

    <p>Strainer housing drain valves</p> Signup and view all the answers

    What is the purpose of using a deflector at each liner water inlet in the cooling system?

    <p>To prevent direct impingement of water on the inner liner wall</p> Signup and view all the answers

    Which components of the engine cooling system are responsible for circulating coolant through the system?

    <p>Water pumps and inlet water manifolds</p> Signup and view all the answers

    What role do the inlet water manifolds play in the cooling system?

    <p>They supply coolant to individual cylinder liners</p> Signup and view all the answers

    Where does the coolant go after it absorbs heat from the engine components?

    <p>It is directed to the radiators for heat exchange</p> Signup and view all the answers

    What component is primarily driven by the governor drive gear in the engine cooling system?

    <p>Centrifugal water pump</p> Signup and view all the answers

    What happens to coolant flow when the engine is first started?

    <p>Coolant begins to circulate through the entire system</p> Signup and view all the answers

    What component connects the water outlet elbows to the water inlet of the manifold?

    <p>Water inlet tube assembly</p> Signup and view all the answers

    Which of the following characteristics is NOT a basic requirement for coolant in EMD engines?

    <p>Forms scale or sludge deposits</p> Signup and view all the answers

    What is the primary form of corrosion inhibitor recommended for EMD engines?

    <p>Borate-nitrate</p> Signup and view all the answers

    How should powder and pellet form corrosion inhibitors be prepared for use in the cooling system?

    <p>Dissolved in water before adding</p> Signup and view all the answers

    What level of borate-nitrate concentration must be maintained in EMD engines?

    <p>Above 5625 parts per million</p> Signup and view all the answers

    Which water processing method is essential before using it in EMD engine cooling systems?

    <p>Softening or de-ionizing</p> Signup and view all the answers

    Which of the following water sources is least likely to be suitable for EMD engine cooling systems?

    <p>Water with excessive hardness salts</p> Signup and view all the answers

    Why is regular analysis of coolant samples important?

    <p>To maintain the proper solution of corrosion inhibitor</p> Signup and view all the answers

    Which of the following does NOT belong to the components of a suitable coolant for EMD engines?

    <p>Heavy metals</p> Signup and view all the answers

    What is the consequence of using water with corrosive elements in the cooling system?

    <p>Increased scale formation</p> Signup and view all the answers

    What is a potential issue caused by using inadequate coolant in an EMD engine?

    <p>Increased wear on engine components</p> Signup and view all the answers

    What is the primary advantage of pressurizing the cooling system in diesel engines?

    <p>It increases the boiling point of the coolant and prevents cavitation.</p> Signup and view all the answers

    What does a progressive lowering of water in the gauge glass indicate?

    <p>There is a potential water leak in the cooling system.</p> Signup and view all the answers

    How is the cooling system of a blower type engine different from a turbo type engine?

    <p>It lacks aftercoolers and associated piping.</p> Signup and view all the answers

    What is the purpose of the pressure cap in the expansion tank?

    <p>To regulate system pressure to specific psi levels.</p> Signup and view all the answers

    What should not occur with the water level in the cooling system during normal operation?

    <p>It should go beyond the 'low' water level mark.</p> Signup and view all the answers

    What is one reason some older marine installations use unpressurized systems?

    <p>They lack modern pressure regulation technologies.</p> Signup and view all the answers

    What characteristic is essential for maintaining optimal operation in the cooling system?

    <p>Ensuring that the system can handle variations in pressure.</p> Signup and view all the answers

    Which of the following components is part of the water circulation process in diesel engines?

    <p>The air compressor.</p> Signup and view all the answers

    Why should water levels in the cooling system be reported if they drop below the 'low' mark?

    <p>To avoid potential engine overheating due to insufficient coolant.</p> Signup and view all the answers

    What feature of the EMD engine water pumps eliminates the need for maintenance?

    <p>Permanently sealed grease lubricated ball bearings</p> Signup and view all the answers

    What is the overall function of the centrifugal pumps used in EMD engine cooling systems?

    <p>To circulate coolant through the engine</p> Signup and view all the answers

    How is the rotation of the water pump in EMD engines characterized?

    <p>It rotates in the opposite direction of the engine crankshaft</p> Signup and view all the answers

    Which of the following components is NOT part of the EMD engine water pump assembly?

    <p>Turbochargers</p> Signup and view all the answers

    What provides support for the water pump drive shaft in EMD engines?

    <p>Ball bearings</p> Signup and view all the answers

    What ensures the functionality of the EMD engine water pumps as self-draining components?

    <p>Geometric design of the pump housing</p> Signup and view all the answers

    How many water pumps are used on EMD engines with eight cylinders?

    <p>One</p> Signup and view all the answers

    Which document provides specifications for antifreeze in EMD engines?

    <p>M.I. 1748</p> Signup and view all the answers

    What component is primarily responsible for maintaining the integrity of the water pump's circulation?

    <p>Impellers</p> Signup and view all the answers

    What is a key operational characteristic of the water pumps in EMD engines?

    <p>They operate at a fixed speed</p> Signup and view all the answers

    Study Notes

    Cooling System Introduction

    • The cooling system circulates water using an engine-driven centrifugal pump.
    • Individual jumper lines connect water manifolds to each cylinder liner.
    • The outlet manifold circulates the coolant.
    • The pump is mounted on the accessory drive housing and driven by the governor drive gear.
    • Illustrations of the engine cooling system are shown in figures 5.1A and 5.1B.

    Cooling System Components

    • Water Pump: Part of the system.
    • Water Inlet Elbow: Guides water flow.
    • System Drain Flange: Outlet for system drainage.
    • Water Inlet Manifold: Distributes water to liners.
    • Water Inlet Tube: Carries water to each liner.
    • Liner Water Passage: Channels water through the liner.
    • Cylinder Head: Houses water passages.
    • Cylinder Head Outlet Elbow: Carries water away from the head.
    • Water Discharge Manifold: Collects water from the cylinders.
    • Water Line To Aftercoolers: Conduit for coolant.
    • Right Bank Aftercooler: Part of the cooling system located on the right engine bank.
    • Aftercooler Water Discharge: Water outlet from the aftercooler.
    • Air Compressor: Receives piping from the water pumps.

    Cooling System Operation

    • Coolant is drawn from the expansion tank through an aspirator.
    • Each manifold connects to aftercooler water inlet pipes.
    • Coolant is supplied to each cylinder liner individually through a water inlet tube.
    • Water flows upward through the cylinder liner's jacket and into the cylinder's head.
    • A discharge elbow carries water to the water discharge manifold, which runs along the top of the crankcase.
    • The siphon tubes inside the manifold drain coolant in the event of an uneven engine.

    Additional Cooling Systems

    • Turbo engines circulate coolant through the aftercooler cores, affecting engine performance.
    • Inlet air temperature is crucial; lower temperatures lead to better performance.
    • Two-pass aftercoolers were used on older EMD engines to cool intake air.
    • Coolant is drawn from the main cooling manifolds after the power assemblies.
    • Four-pass aftercoolers offer higher cooling capacity and balanced coolant flow.
    • The coolant returns to the lube oil cooler to absorb excess heat before returning to the aspirators.

    Blower Type Cooling System

    • The cooling system design is similar between blower and turbo types; it lacks aftercoolers.
    • The system piping and associated components are shown in Figure 5.3.

    Cooling System Pressure

    • Modern systems use pressurized coolant to increase boiling points and prevent cavitation during high temperatures.
    • Older systems, on the other hand, were not pressurized.
    • Typical pressure values range from 7 to 20 psi (48 to 138 kPa).

    Coolant Analysis and Requirements

    • Coolant includes water, corrosion inhibitors, and potentially antifreeze.
    • Coolant samples are analyzed to check for proper corrosion inhibitor levels.
    • Proper coolant must maintain adequate heat transfer, prevent sludge deposits, and prevent corrosion inside the cooling system.

    Water Analysis

    • Water sources containing higher amounts of solids, hardness salts, or corrosives are not suitable for cooling systems without treatment.

    Corrosion Inhibitors

    • Borate-nitrate is a common inhibitor type used in EMD engines, available in powder, pellet, and liquid form.

    Antifreeze and Water Pumps

    • Specifications for antifreeze are available in MI 1748.
    • Water pumps are centrifugal and self-draining.
    • The pump drive shaft contains permanently sealed ball bearings.
    • Components of the pump are detailed in figure 5.5.

    External Water Leaks (Troubleshooting)

    • External water leaks should be systemically checked.
    • Check engine components, flanges, pipes, for visual signs of leaks.
    • Check cooling lines, expansion tank, and water pumps for leaks.
    • Verify all related hoses and connections.

    Internal Water Leaks (Troubleshooting): Running Engines

    • Check water discharge elbows, core plugs, lifting holes, and injector wells for leaks.
    • Examine cylinder heads, engine block, and manifolds for cracks.
    • Inspect the top of cylinder heads; look for cracks or leaks.
    • Examine water manifolds for leaks or cracked 'O' rings.

    Pressure Tests

    • Perform 25psi hydro-tests.
    • Perform 90psi block tests (for engines with potential oil/water contamination issues).

    High Coolant Temperature Troubleshooting

    • Check coolant levels.
    • Check for internal/external leaks.
    • Verify proper fan and switch operation.
    • Inspect radiators for airflow restrictions.
    • Inspect coolant lines for proper connections and loose fittings.
    • Check coolant levels and look for signs of leaks from the cooling system.

    Low Coolant Pressure Troubleshooting

    • Install a pressure gauge in the expansion tank.
    • Compare the reading to the stamped pressure on the cap.
    • Inspect the expansion tank vent valve.
    • Inspect the filler neck and related components for leaks.

    System Maintenance

    • Daily checks of coolant levels.
    • 90-day inspections for corrosion inhibitor strength.
    • 6-month inspections for radiator cleanliness and foreign material removal.
    • Annual inspections for radiator header screen cleaning and pressure tests.
    • 2-year checks of filler necks.
    • 3-year checks of water pumps, flexible pipes, and control/operating components.

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    Description

    Dive into the fundamental components and functions of an engine cooling system. Learn about the various parts, such as the water pump and manifolds, and how they work together to maintain engine temperature. This quiz is essential for understanding cooling mechanics in automotive engineering.

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