CLARK FORKLIFT IClOO Cooling and Exhaust Systems TECHNICAL TRAINING MANUAL

IClOO Cooling and Exhaust Systems

TECHNICAL TRAINING Copyrighted Material Intended for CLARK dealers only Do not sell or distribute

Copyrighted Material Intended for CLARK dealers only Do not sell or distribute

Contents

About this class ..........................................................................................

About safety .............................................................................................

Section 1. The Cooling System ..................................................................

The Cooling System .............................................................................

Coolant .................................................................................................

Water Pump ........................................................................................

Thermostat ............................................... ........ .................. ................

Radiator Core .....................................................................................

Transmission Oil Cooler ......................................................................

Radiator Pressure Cap ........................................................................

Overflow Pipe and Coolant Recovery Bottle ........... ......................... .

Hoses and Clamps ....................................................... ........................

Cooling Fan ..........................................................................................

Fan Shroud ..........................................................................................

Fan Belt ...............................................................................................

Fan Belt Adjustment.............................................................................

Sender and Gauge ...............................................................................

Viscous Fan Drive ...............................................................................

Section 3. Troubleshooting the Cooling System ........................................

Five Basic Steps to Troubleshooting....................................................

Physical Inspection with the Engine Off ...........................................

Physical Inspection with the Engine Running ..................................

Pressure Testing the Cooling System..................................................

Testing the Thermostat ......................................................................

Checking the Timing ...... .................................................................... .

Checking the Viscous Fan Drive ........................................................

Using the Cooling System Analyzer ..................................................

Reverse Flow Flushing .......................................................................

Reverse Flow Flushing the Radiator .................................................

Reverse Flow Flushing the Engine Jacket ........................................

Section 4. The Exhaust System .................................................................

Exhaust Manifold ................................................................................

Exhaust Pipe ................................................................. ......................

Muffler .................................................................................................

Tail Pipe ...................................................................... .........................

Catalytic Converter (Optional) ...........................................................

Piccolo Tube Tail Pipe ......... ........................................................ .........

Section 5. Troubleshooting the Exhaust System .......................................

Troubleshooting the Exhaust System ...... ..........................................

Section 6. Easy Reference Troubleshooting ..............................................

Easy Reference Troubleshooting ........................................... .............

Engine Overheats ................................. ...............................................

Engine Runs Cold ................................................................................

Water Pump :Leaks .............................................................................

Water Pump Makes Noise ..................................................................

Oil in Coolant ......................................................................................

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3 4 5 5 5 6 7 8 10 11 12 13 14 15 15 15 16 17 19 19 19 22 22 23 24 24 24 26 26 26 28 28 29 29 30 31 31 32 32 33 33 33 35 35 35 36 IC 100 page 1

Coolant in Engine Oil ..........................................................................

Coolant in Transmission Fluid .......................................... .................

Noise and Fumes .................................................................................

Back Pressure ......................................................................................

Exhaust System Rattles ......................................................................

Copyright Clark Material Handling Company 1990 Revised 1998

IC 100 page 2

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36 36 36 36 26

About this class

The cooling and exhaust systems play a vital role in the proper functioning of the internal combustion engine. Because the sources of problems with these systems are hard to de­ termine, this class will teach you the theories behind the components of the cooling and exhaust systems and show you how to troubleshoot each system.

The engine runs because of the energy and heat created in the combustion chamber when the spark plug ignites the fuel. However, only a small amount of this heat is turned into useful mechanical work. For the engine to function properly, the excess heat must be removed.

The cooling system's main function is to control the operating temperature of the engine.

It removes excess heat in the cylinder block by transfen'ing the heat to a coolant solution in the engine water jacket. The heated coolant leaves the cylinder block and enters the radiator where air blown through the radiator core removes the heat from the coolant and expels it from the system.

The exhaust system has two p1'imary functions. To reduce noise and to direct exhaust away from the operator and engine.

When you have finished this class and passed the w1'itten test, you will have learned three things: 1. You will know how the components of the cooling and exhaust systems work.

2. You will be familiar with the problems associated with these components.

3. You will know how to troubleshoot these systems.

After you have finished this class, you can use this manual as a handy reference guide.

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IC 100 page 3

About safety

The following messages will be used to emphasize important information: Note This message is used when special information, instructions or identification is required relating to procedures, equipment, tools, pressures, capacities and other special data.

Important This message is used when special precautions should be taken to ensure a correct action or to avoid damage to or malfunction of the truck or a component.

CAUTION This message is used as a reminder of safety practices that if not followed can result in personal injury.

WARNING This message is used when a hazard exists which can result in injury or death if proper precautions are not taken.

DANGER

This message is used when an extreme hazard exists which will result in death or serious injury if proper precautions are not taken.

CAUTION Working with the heating and cooling systems will expose you to

conditions that could result in personal injury. The two most common personal injury accidents associated with the cooling and exhaust systems are getting burned and getting caught in a moving part. Please observe the following safety measures while working on the cooling and exhaust systems.

Hot coolant or steam can cause severe burns. If possible, avoid touching or working on any part of the cooling system until it has an opportunity to cool (approximately four hours after the last use). If you must work on a hot system, you should relieve the built-up pressure by carefully opening the radiator cap. Cover the radiator pressure cap with a rag and turn it slowly to the first stop. This will let the pressure out of the cooling system before removing the radiator cap. Be careful not to expose any body parts to steam or coolant escaping from the radiator. Total arm covering is required.

Whenever possible, work with the engine turned off. If a situation arises where you have to work on the cooling or exhaust systems while the en­ gine is running, be sure to observe the following safety procedures: place the transmission in neutral, engage the parking brake, lower the forks onto the floor, and double block the wheels. Moving parts can cause injury!

Keep hands, arms, and clothing away from rotating belts and fan. Never wear loose clothing. Tie back long hair while inspecting the belts and fan.

Avoid wearing rings, watches and jewelry. Don't stand inline with a rotating fan. Exhaust parts are hot and could cause severe burns.

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SECTION 1 THE COOLING SYSTEM

The engine cooling system consists of the radiator, fan and drive belt, thermostat, water pump and assorted hoses. The radiator is filled with a coolant solution and capped. Addi­ tional coolant is put into an overflow bottle. (a reservoir that allows for fluid expansion as the coolant is heated by the engine).

The cooling system controls the engine's heat by using a mixture of 50% ethylene glycol and 50% water, which is circulated by a water pump and regulated by a thermostat.

When the engine is cool, the thermostat is closed and the coolant circulates in the engine block by means of a by-pass circuit, which connects the thermostat housing to the water pump. This small circuit ensures that temperature will be distributed evenly in the en­ gine block while the thermostat is closed.

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Cooling System

When the engine is warm, the water pump forces coolant into the front of the block and between the cylinder bores. When the coolant leaves the cylinder head, it enters the thermostat, which regulates its flow to the radiator. Since most engines work best at temperatures between 180° and 200° F (81° and 93° C) the thermostat is constructed to begin opening at 180° and to be fully opened at 202° F. The heated coolant leaves the opened thermostat, circulates through the radiator, and transfers its heat to the air forced through the radiator core by the radiator fan. The cooled fluid then flows through the system again.

Coolant

Using a good coolant is vital to the proper operation of an engine. We recommend a coolant solution of 50% water and 50% ethylene glycol. This mixture is preferable to a 100% water solution for five reasons: Copyrighted Material Intended for CLARK dealers only Do not sell or distribute

IC 100 page 5

1. The coolant solution lowers the freezing temperature from 32° F. to approximately -30 ° F (0° to -35° C). If a 100% water solution is used, freezing will cause the water to expand 9% which could result in cracking the engine block or radiator core.

2. The coolant raises the solution's boiling point from 212° F (100 ° C) to approximately 220° F (106° C). This higher boiling point creates a higher cooling capacity.

3. The coolant will prevent rust and corrosion from forming in the radiator core and in the engine.

4. The coolant prevents the formation of foam or air bubbles in the system.

5. The coolant contains an ingredient that lubricates the water pump seal and prolongs the seal's life.

Important Under no condition should a vehicle operate without a minimum of 50% ethylene glycol to a maximum of 65% ethylene glycol solution.

We recommend using quality antifreeze manufactured by a reputable company. We also recommend using antifreeze with low silicate compound. Many low quality coolants con­ tain high concentrations of silicate compounds that can damage the water pump seal.

For the cooling system to perform at top efficiency, we recommend that the coolant is changed and the radiator flushed after a maximum of 2,000 hours of operation or at least once year.

Water Pump The water pump, which is mounted on the front of the cylinder block, is the driving force of the cooling system. The water pump propels the coolant through the cooling system.

How it works When the engine is hot, the pump draws coolant from the radiator through the lower radiator hose and forces it through passages in the cylinder block.

The pump consists of six parts: (1) housing, (2) seal, (3) pulley, (4) drive shaft, (5) bearing, and impeller.

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The pump receives its power from the fan belt, which transfers energy from the crank­ shaft pulley to the water pump pulley. The water pump bearing allows the pulley and drive shaft to turn. The bearing is permanently sealed and requires no lubrication. The drive shaft is connected to an impeller which forces water from the radiator into the cylinder block.

The impeller is enclosed in either aluminum or a cast iron housing by a seal that prevents coolant leakage. If the housing is damaged or the seal broken, the system will lose coolant and the engine will overheat. Coolant contains a lubricant that helps extend the life of the water pump seal surfaces.

Related Problems The water pump requires little attention other than replacing worn bearings or leaking seals.

1. If the fan belt is too tight, premature wear of the water pump bearing could result.

Whenever a bearing burns out, replace the bea1ing and the seals or replace the pump.

2. If water pump seal leaks because of lack of lubrication or extended use, replace either the seal or the pump.

3. If no antifreeze is used, the impeller can be dissolved by con-osion. If the impeller is impaired in any way, the coolant flow will be dramatically reduced and the engine will not cool properly. If the impeller is damaged, either replace the impeller or replace the pump.

4. If the housing is cracked, the cooling system will lose coolant. Any loss of coolant can cause an overheating condition. Replace the pump assembly.

Thermostat The thermostat, which is housed in the cylinder block, is a device that restricts water circulation until the temperature of the cylinder block reaches a temperature that is compatible with the thermostat.

&Elbow Gasket� Thermostat Housing�

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IC 100 page 7

How it works

Most engines operate best at temperatures between 180 ° and 200° F. (81° and 93° C.) When the coolant in the cylinder block reaches the thermostat temperature, the thermo­ stat begins to open. This allows heated coolant to circulate through the engine block, radiator and the rest of the cooling system.

The thermostat will open when the temperature rating of the thermostat is reached. In most systems, a thermostat of 180° is used.

Related Problems

1. If the thermostat does not open properly and the coolant in the engine block is not allowed to flow to the radiator, the engine will overheat. This could cause serious damage to the engine block.

2. If the coolant is circulated before the engine warms up, the engine will run cold. If the engine runs cold, water in the coolant can condense and form acid compounds. These acids can dilute the oil, corrode engine parts, and reduce the life of the engine. A cold engine will use more fuel and emit more hydi·ocarbons and carbon monoxide. A similar problem could occur in the transmission if not corrected.

3. If the thermostat is removed from the system and not replaced, four problems could develop: The engine will run cold when first started (because there is no thermostat to keep the coolant in the engine block until it reaches the minimum operating temperatw·e.

The engine will take longer to warm up (or may never warm up in cold climates).

The engine will run hot after it warms up (because the coolant will flow too swiftly through the radiator to lose the heat it's acquired).

The transmission oil temperature could be sub-cooled (especially in cold weather), which could cause moisture to form. This moisture could reduce the transmission's life.

Radiator Core

When the thermostat opens, heated coolant is allowed to flow from the engine into the radiator core. The radiator core transfers the heat from the coolant to air being blown through the radiator core by the radiator fan.

How it works

The radiator core consists of a series of metal tubes through which the heated coolant is circulated. Fins are attached to the tubes to create extra surface areas that enable the coolant to transfer more heat to the air.

The coolant transfers its heat to the tubes and fins which in turn transfer the heat to the air. The cooled coolant is then sent back to the engine block.

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