Water Pump - A device, usually located on the front of the engine and driven by oneof the accessory drive belts, that circulates the coolant by causing itto move from the lower radiator-outlet section into the engine bycentrifugal action of a finned impeller on the pump shaft.
The majority of water pump failures are attributed to leaks of somesort. When the pump seal fails, coolant will begin to seep out of theweep hole in the casting.
Signs of leakage from the water pump vent means the pump's seal is bad. Courtesy of Federal-Mogul Corporation.This is an early indicator of trouble. The seals may simply wear outdue to abrasives in the cooling system, or some types of seals crackdue to thermal shock such as adding cold water to an overheated engine.This could also cause other internal parts to fail.
Other failures can be attributed to bearing and shaft problems andan occasional cracked casting. Water pump bearing or seal failure canbe caused by surprisingly small out-of-balance conditions that aredifficult to spot. Look for the following:
- A bent fan. A single bent blade will cause problems.
- A piece of fan missing.
- A cracked fan blade. Even a small crack will prevent proper flexing.
- Fan mounting surfaces that are not clean or flush.
- A worn fan clutch.
To check a water pump, start the engine and listen for a bad bearing, using a mechanic's stethoscope or rubber tubing.
WARNINGWhenever working near a running engine, keep yourhands and clothing away from the moving fan, pulleys, and belts. Do notallow the stethoscope or rubber tubing to be caught by the moving parts.There is another test that can be performed on vehicles with an engine-driven fan.
- Place the stethoscope or hose on the bearing or pump shaft.
- If a louder than normal noise is heard, the bearing is defective.
- With the engine off and the fan belt and shroud removed, grasp the fan and attempt to move it in and out and up and down.
- More than 1/16 inch (1.58 mm) of movement indicates worn bearings that require water pump replacement.
- To determine whether the water pump is allowing for good circulation, warm up the engine and run it at idle speed.
- Squeeze the upper hose connection with one hand and accelerate the engine with the other hand.
- If a surge on the hose is felt, the pump is working.
- Any air being sucked into the cooling system is certain to have a detrimental effect.
- It cuts down pumping efficiency and causes both rusting and wear at a rate approximately three times above normal.
- To test for aeration, have the engine fully warmed up, all hose connections tight, and the coolant level up to normal.
- Attach one end of a small hose to the radiator overflow pipe and put the other end into a jar of water.
- Run the engine at a fast idle. If a steady stream of bubblesappears in the jar of water, air is getting into the cooling system.
- Check first for a cylinder gasket leak by running a compression test.
- If two adjacent cylinders test low, the gasket is bad. Otherwise, there is an air leak somewhere else in the cooling system.
- When replacing a water pump, it is necessary to drain the cooling system.
- Any components--belts, fan, fan shroud, shaft spacers, or viscousdrive clutch--should be removed to make the pump accessible. Some pumpsare attached to the cylinder block as shown below.
Installing a water pump. Courtesy of Dana Corporation.
WARNINGWhen working on the coolant system (for example,replacing the water pump or thermostat), a certain amount of coolantwill spill on the floor. The antifreeze in the coolant causes it to bevery slippery. Always immediately wipe up any coolant that spills toreduce or eliminate the chance of injury.
- Loosen and remove the bolts in a crisscross pattern from the center outward.
- Insert a rag into the block opening and scrape off any remains of the old gasket.
To be really honest, it depends on person to person. For some people it's easy and for some it's tough. The procedure is above for your model. You can judge yourself.
- When replacing a water pump, always follow the procedures recommended by the manufacturer.
- Most often a coating of good waterproof sealer should be applied toa new gasket before it is placed into position on the water pump.
- Coat the other side of the gasket with sealer, and position the pump against the engine block until it is properly seated.
- Install the mounting bolts and tighten them evenly in a staggeredsequence to the torque specifications with a torque wrench. Carelesstightening could cause the pump housing to crack. Check the pump tomake sure it rotates freely.
- The water pumps on many late-model OHC engines are driven by theengine's timing belt. When replacing the water pump on these engines,always replace the timing belt.
- Make sure all pulleys and gears are aligned according to specifications when installing the belt.
Hope i helped you.
Thanks for using ' Fixya ' and have a nice day!!