Hub Attached to the bearing assembly is the hub which is the connecting source of power for impeller rotation. Bearing Assembly The bearing assembly is the mechanical support for continuous rotation of the impeller. Housing The housing is the outer shell that encases the pump. It is typically made of cast iron or aluminum materials, although a number of modern pumps use stamped-steel housings. Seal The seal protects the bearing assembly from coolant and contaminants. Impeller The impeller spins and distributes coolant throughout the cooling system. Built for Extremes of Heat, Cold and High Demand It makes a difference to install Bosch 100% New. Installing a 100% new water pump can restore a cooling system to proper working order and will minimize the risk of premature failure. Remanufactured performance can compromise the system, reduce cooling capability and cause damage to the engine. Feature Benefit Unitized seals Provides exceptional protection against leakage and contamination Precision pressed hub and impeller For added performance and longer pump life Precision ground, unitized bearing assembly Withstands stress Precision machined mounting surfaces For proper sealing Gaskets and hardware included For accurate, easy installation
Thermostat Housing Radiator Heater Core Heater Hose Heater Valve Water Pump Radiator Hose Fan Clutch Built for Extremes of Heat, Cold and High Demand Bosch Premium - 100% new, OEM-quality components. The water pump is a precision component in the cooling system, designed to work in a highly stressful environment to keep a vehicle s circulation system cool and functioning. That s why Bosch include only new, OEM-quality components. And, every Bosch Water Pump meets or exceeds original equipment specifications. Each pump undergoes extensive on-line testing to ensure optimum performance. You can count on Bosch 100% New for superior performance and maximum service life. Trust the experience of Bosch. For over 100 years the name Bosch has been associated with the automobile. From high performance spark plugs, to wiper blades, oxygen sensors, starters, alternators, spark plug wire sets and more, the Bosch brand is recognized for premium quality.
Information How to Measure Hub Height The hub height is the measure - ment from the pump s mounting surface (where it mates to the engine), and the top of the hub surface (where the pulley mates to it). Warning 0 1 HUB HEIGHT To properly service cooling system: Use only the maintenance techniques, instructions and specifications in the Vehicle Manufacturer s Factory Service Manual and Service Bulletins. Use only correct replacement parts. Do not make substitutions or modifications to parts. Refer to the Bosch Catalog. Use only correct anti-freeze/coolant as specified by the vehicle manufacturer. Disclaimer The specifications and information shown in this and other Bosch manuals have been obtained from reliable sources, and are believed to be accurate at the time of publication. No guarantee or warranty, expressed or implied, is made as to the accuracy of the information and Bosch cannot and does not accept or assume any responsibility for errors, omissions or consequential harm resulting therefrom. Replacement parts should not be used when they do not appear to fit. Under no circumstance should a replacement part be forced or modified to fit. Should any questions arise regarding specifications in this catalog, consult the appropriate Vehicle Manufacturer s Factory Service Manual and Service Bulletins.
Standard or Reverse Rotation Water Pump When determining if it is a STANDARD or REVERSE rotation water pump, please refer to the belt path diagram under the hood. This is typically located on the fan shroud, or on the front fender brace. Otherwise, locate the water pump pulleys on the vehicle. Compare the diagram below. Water pump pulleys on the INSIDE surface of the belt indicate a STANDARD ROTATION water pump. Water pump pulleys running on the OUTSIDE surface of the belt indicate a REVERSE ROTATION water pump. WARNING Technical Information Standard and reverse rotation water pumps are not interchangeable. Serious engine damage can result from using the wrong pump. SERPENTINE OR"V" BELT SERPENTINE BELT CRANK WATER PUMP WATER PUMP CRANK Standard Rotation Water Pump (Inside of Belt) For example: 97080, 98060, 99105 Reverse Rotation Water Pump (Outside of Belt) For example: 97081, 98059, 99121 When answering the question, is this a standard or reverse rotation water pump?, the customer s own vehicle will have the clearest answer. A belt path diagram is located under the hood on most late model light trucks and automobiles. Find the water pump pulley on the diagram, or look on the front of the engine if you cannot find the diagram. Simply determine if the water pump is driven by the outside or inside of the belt. Square or Routh Tooth Belt Design Refer to below illustration: 97114 is used on vehicles having a timing belt and water pump pulley with a rounded edge tooth design. 97037 & 97112 are used on vehicles having a timing belt and water pump pulley with a square tooth design. NOTE: These water pumps are not interchangeable. Round Tooth Design Square Tooth Design 97114 For example: 97037 97112
Installation Information Tips for Installing a Water Pump BEFORE installing a new water pump, remember the following: If the old pump will still circulate coolant through the engine, always clean the cooling system with a chemical cleaner and reverse flush all sediment, rust, and scale before removing the old pump. Failure to do so can result in premature seal failure in the new pump due to a dirty system. On cars equipped with timing belts, care must be taken when removing the water pump so that engine timing is not disturbed, which would result in internal engine damage. Clean out any built up sediment and scale from the impeller cavity in the engine block. FAN ASSEMBLY WATER PUMP GASKET FAN CLUTCH WATER PUMP ENGINE FRONT COVER When installing the new pump, remember: Do not force the pump on by striking the end of the shaft. Tighten mounting bolts gradually and evenly in a staggered sequence to the vehicle manufacturer s torque specifications. Do not over torque bolts, which may result in fractures caused by sudden overload. It is important to check the condition of the current fan clutch, fan, and fan belt tensioner. If any of these items appear to be worn, damaged, or imbalanced, replace them. Failure to do so can result in early failure or damage to the new pump. Never adjust belts tighter than specified in the factory service manual. Excessive tightening of belts running over the water pump pulley is the major cause of premature bearing failure and breaking of the bearing shaft or housing. On models equipped with automatic belt tensioners, be sure to inspect and test the operation of the tensioner prior to reusing. Most vehicle manufacturers have testing procedures or specifications for these tensioners. Turn pump shaft to make sure it rotates freely before reinstalling pulleys, fans, clutches, belts, and hoses. Fill the radiator and coolant recovery bottle with a correct mixture of fresh low silicate coolant and distilled water and check for leaks. Be sure you measure the amount of coolant mixture that you have added so you can track if there is any air in the system. Purge system of air as required. Note that a small, temporary seepage of coolant from the weep hole may occur during the initial run-in period. This should stop after the seal has been allowed to lap in. After operating temperature has been reached, shut off engine and allow it to cool - Never remove the radiator cap while engine is hot. Adding cold coolant to a hot system may damage the seal. Always refer to your manufacturers repair manual for the exact procedures and specifications when replacing a water pump. Finally, always replace the antifreeze when installing a new water pump. Match the type of antifreeze to the manufacturer s specification. Never substitute or mix types of antifreeze. Also, it is not recommended to use chemical additives.
Regular inspection and maintenance of the cooling system should detect early signs of component wear or damage. This general troubleshooting guide deals with the most common and obvious signs of cooling system trouble: overheating and inadequate circulation. Some specific examples of possible causes are provided in the Water Pump Failures and Their Causes section. For other cooling system related symptoms and more specific analysis, see the vehicle manufacturer s service manuals. Overheating Coolant Leakage Loss of coolant is one of the major causes of engine overheating. This leakage allows pressure to bleed out of the system, which lowers the boiling point of the remaining coolant. This also allows air to enter the system and reduces the cooling efficiency; as it actually insulates and traps heat in the system. Regular inspection of cooling components can often detect early leakage problems. Therefore, directly identifying the damaged or worn component before it causes failure or overheating is important. Here are some of the key areas to check for leakage during normal periodic maintenance: Radiator core and tanks - look for signs of leakage or damage of cooling fins and tubes, plus welded seams. Hoses and connections Check condition of all hoses and inspect tightness of all clamps. Water Pump Carefully check for leaks at gasket surface and at the water pump weep hole. If the source of the external leakage is not detectable, refer to factory service manual for procedures to detect possible leakage inside engine block. Inadequate Circulation If overheating does not appear to have been caused by coolant leakage, then this buildup of engine waste heat may be related to either: 1. a poor circulation of coolant, or 2. to a lack of airflow through the radiator. Here s how to check: Coolant Circulation Allow the engine to warm to operating temperature. With engine idling, firmly grasp the upper radiator hose to momentarily restrict its flow. (Be careful, it may be hot!) Slowly relaxing your grip, you should feel a surge of coolant going through the hose. This indicates that the coolant is being properly circulated by the pump and that the thermostat is open. If the hose is warm but the surge is not felt, the pump may not be properly circulating the coolant and may need to be replaced. If the hose remains cold when the engine is fully warmed, the thermostat may be inoperative and should be replaced before the system is retested. NOTE: Before performing this test, observe the relationship between the fan and hose. Some vehicles may be unsafe to test in this manner because of the proximity of the fan to the upper hose. Never reach around, or place hands or clothing close to the turning fan. Air Circulation With the engine turned off, check the radiator cooling fins for restrictions. Shine a bright light from the fan side of the radiator and observe from the other side - this should reveal any obstructions such as dirt or bugs. Spraying with a hose from the fan side should dislodge these particles. If the radiator fins appear to be clean, then the radiator may need to be removed and examined for leaks or restrictions by a radiator specialist. However, the fan clutch can be another cause of poor air circulation and should be first examined. Troubleshooting NOTE: On FWD vehicles, the electric fan can be programmed to operate for specified periods under specific operating conditions. For instance, many fans will operate even after the engine has been turned off to provide proper cooling. Consult the factory service manual before evaluating electric fan operation. Water Pump Failures and Their Causes Seal Leakage-Dirty System Evidence of seal leakage from weep hole This pump has been in service only a short time before rusty-looking coolant began to leak out of the weep hole, leaving behind large deposits of rust and calcium. The figure below shows a buildup of rust particles with a mud-like consistency within the pump. Cooling System Contamination Build-up of contaminants quickly wear seal 1 1 The abrasiveness of the particles found in a badly contaminated system will prematurely wear the water pump seal. Harmful contamination is common in systems that are not properly maintained. A system
Troubleshooting that is not properly pressurized will allow air to enter and promote the build-up of rust. If water with a high mineral content is added to the system and is heated, it will begin to form deposits that will accumulate and cause passage restrictions which may damage the seal. 1 Thoroughly flush a contaminated system BEFORE replacing the water pump. Check system pressure, use correct coolant mixture, and consider using demineralized or distilled water where locally deemed necessary. Shaft Breakage 2 prior to shaft breakage. This heat build-up can be caused by the tremendous centrifugal forces created by imbalance. This overloads the bearing generating a great deal of heat. This load is amplified through rapid acceleration and high RPM operation. 2 Carefully check alignment of all pulleys. Also check the pulleys for straightness or fatigue. Install belts using a belt tension gauge according to manufacturer s recommendations. Carefully inspect fan/fan clutch assembly for a bent or damaged fan, a worn spacer, or a worn or damaged fan clutch. Be sure to evenly tighten the mounting bolts to manufacturer s specifications. Casting Breakage 3 Seal Leakage-Clean System Leakage was observed from this 4 pump, which had just recently been installed in a fairly clean coolant system. Thermal Shock The seal was more closely inspected after no signs of contamination 4 were observed. This revealed that the seal damage had come from thermal shock, typically caused by adding cold coolant to an overheated engine. The damage appears as Clean break indicates an instantaneous fracture caused by sudden overload or imbalance. A break usually occurs through the front bearing race portion of the shaft. This particular break can be noted by a clean fracture, rather than blue heat discoloration, which can appear in this same type of failure. 2 Bearing Overload This bearing failed as the result of a sudden overload caused by vibration or imbalance. The lack of heatrelated discoloration indicates that this was sudden rather than gradual, and was probably compounded by rapid engine acceleration. Blue discoloration of the shaft would indicate that there was excessive heat build-up for some period Excessive vibration This shattered breakage this casting. will normally occur around the bearing support. Excessive Vibration Casting failure is normally associated with heavy vibration or imbalance which can be caused by a badly worn fan clutch or bent fan. Carefully inspect pulley, belt alignment and fan / fan clutch assembly, 3 replacing any bent or worn components. 3 Adding cold coolant to a hot system can crack a ceramic seal a diametrical crack across either the seal face or the mating ring. This can also occur following water pump replacement if the engine is started before adding coolant. Take proper precautions when filling your radiator, especially when the engine may 4 be very hot. Allow an overheated engine to sit and cool before adding coolant. Then, restart engine and allow it to run while slowly adding the remainder. NEVER start the engine without coolant. Many Bosch water pumps have a sintered iron mating face or seal which is much more resistant to shock than the ceramic material commonly used by other manufacturers.