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October 9, 2009
Water Pumps
Failures Happen
As part of the cooling system, the water pump is pretty important in keeping the vehicle running in good order. Summer is coming, and you need to be on the lookout for symptoms that could suggest the water pump needs replacing. this is also good preventive maintenance.
As you are certainly aware, the water pump can be driven by either the timing belt (on some of the newer vehicles) or the fan belt in order to transport the rad coolant all the way though the engine and then back into the radiator. Since the water pump has a rotor on one end and a shaft with pulley on the other, the rotor is the part that moves the coolant when the belt spins the pulley.
Needless to say, cars can have problems with the cooling system—one of the most common being water pump failure. However, they are pretty tough customers and often last from about 96,000 to 128,000 km. But other things can damage the pump—coolant contamination and cooling system corrosion. The good news is that you can prevent both by regularly checking coolant chemical balance. If the coolant is no longer effective, it needs to be changed. Also, flushing the cooling system on a regular schedule will help reduce coolant contamination failures.
And still more Other causes of pump failure could be…
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The automatic belt tensioner—is it oscillating excessively?
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The shaft—is it broken? This is usually caused by imbalance (rapid acceleration and high rpms).
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Pulley misalignment.
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Broken housing.
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Bearing failure.
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A broken belt.
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A defective fan clutch.
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Continuous seepage from the weep hole which indicates a failed seal.
So you go over all the symptoms of the possible failures above if the failed culprit is not readily visible. Then you need to install a new water pump.
Installing
Before installation, clean out the cooling system. Gates has some great tips in their Water Pump catalogue that will help immensely if this is something new and different for you. They suggest that you disconnect the fan, fan clutch, hoses, and belts and remove the old water pump. Next, you should inspect the impeller cavity in the engine block. You need to clean it thoroughly, removing sediment buildup and scale—don’t forget the gasket surface. They also recommend that you replace the timing belt and components, if the water pump is timing belt driven. Be sure to identify whether it is a standard or reverse rotation pump—they are not interchangeable. You need to tighten the steel back plate bolts and coat the new gaskets with gasket sealer. Don’t strike the pump shaft in order to force the pump. Tighten the mounting bolts to manufacturer’s torque specs.
If the water pump has a fan clutch and belt, take a good look and replace them if you think something is wrong. Don’t overtighten the belts. Test the automatic belt tensioner according to the manufacturer’s instructions. See that the pump shaft rotates freely before reinstalling pulleys, fans, clutches, belts, and hoses. Check for leaks. Check the fan blades—if they are bent, cracked, or if rivets are loose, replace the fan.
Manufacturer’s recommendations
You should follow the manufacturer’s repair manual in replacing the water pump and ALWAYS put in new coolant after a water pump installation. Again, see what the manufacturer recommends, don’t mix types of antifreeze, and don’t use coolant additives.
On the import side of water pumps, Beck/Arnley also offers a full line and suggests replacement tips as well. In fact, they recommend replacing the fan clutch to prevent heating problems. They also say that cooling system failures can be avoided with proper maintenance and replacement of critical components.
Another avenue to look at when sourcing a water pump is remanufactured pumps such as the high quality ones from Fenco.
Our thanks to Gates, Beck/Arnley, and Fenco for the information provided for this article
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