by Art Heberger

Created on: June 23, 2010

Is your car cool? I don't mean; everybody envies you as you drive down the street cool. I mean, your engine parts aren't going to melt cool.

OK, that doesn’t happen…much, but if the water pump doesn't circulate coolant through your engine to keep it within operating temperature, it won't be much good to you.

Low coolant levels can cause an engine to have problems with overheating. Be sure to check your coolant level in the overflow reservoir as often as you check your oil and other fluids. NEVER, remove the radiator cap when the engine is hot! When it is cold, you can check and add coolant, but make sure you replace the cap properly. Your owner's manual should tell you how often your cooling system needs to be drained, flushed and refilled.

The water pump circulates coolant through the engine block, cylinder heads, heater core and radiator. A water pump is mounted on your engine and is driven by a V or serpentine belt attached to the crankshaft. A water pump circulates the coolant continuously, and the rate of circulation is controlled by a thermostat.

A water pump is consists of a housing, shaft, impeller, flange, bearing and shaft seal. Some that are driven by a serpentine belt come with a pulley mounted on the shaft. A gasket or gaskets seal it to the block and there is a neck on the housing to connect the radiator hose. Because the water pump is belt driven, coolant flow increases as the engines RPMs increase.

Warning signs of a failing water pump are a squealing or rattling noise when the engine is running, which could be the shaft bearing failing or the impeller hitting the housing, or if you notice coolant under your car, check to see if it's leaking through the inspection (weep) hole in the pump where the coolant drains when the shaft seal fails.

A water pump operating under those conditions can cause the engine to overheat or the impeller to come apart and cause internal engine damage. So make sure you check it out right away.

Some engines have internal water pumps located under the timing cover and driven by the timing belt. On these engines if you need to check the condition of the water pump, you will need to remove the timing cover.

To check the water pump when it is mounted externally, with the engine off and cold, remove the belt and grab the water pump flange or pulley and try to move it back and forth. You should not feel any significant play in the shaft. If there is the bearing has failed and the water pump needs to be replaced.

Depending on manufacturer recommendations, a water pump will need replacement at between 60,000 and 100,000 miles. Replace your water pump with a high quality lifetime warranted part. You're not saving money if you buy something that's not going to last as long as it should or cause damage to your engine Also be aware that depending on the engine code two cars that are the same make, model and year could take different water pumps.

Because I am running out of space, I will cover replacement in another article.

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