Internal combustion engines run by little explosions. These explosions create extreme heat. That heat can harm the engine if it is not managed. Luckily, the water pump protects against this by circulating coolant in the engine.
But what if the water pump was no longer working? Let’s look at some common symptoms of a bad water pump and the average costs to replace it if necessary.
How a Water Pump Works
With the engine running, coolant from the radiator flows into the center of the water pump. The engine’s crankshaft turns the impeller in a water pump to circulate coolant through the engine, much like a heart pumps blood.
This fluid, or coolant, is forced by the pump vanes into the cylinder head and engine block and back to the radiator, completing the cycle thousands of times/minute. When the water pump has a problem, the result is overheating.
Symptoms of a Bad Water Pump
An overheated engine can quickly lead to engine failure, a very costly outcome. Understanding how water pumps function in cooling your vehicle is important, but knowing the signs that your water pump is failing or is broken is even more important.
#1. High Coolant Temperature.
The most obvious sign of a bad water pump is an overheated engine, which is generally indicated by an engine temperature warning light (or an icon that has wavy lines in it) or high engine temperature while monitoring the dashboard.
A functioning water pump circulates coolant to cool down the engine, so a bad water pump will let engine heat build, instead of dissipating it, especially if the temperature of the system is designed to operate at high temperatures.
Be aware – the temperature gauge in some vehicles won’t move off center until they have already reached dangerous engine temperatures, so beware if you notice the needle rising beyond its normal operating temperature position.
#2. Engine overheating.
If you see steam pouring out of the front of your vehicle whether it is on the move with the engine running or as you are stopped in traffic, it is most likely the result of engine overheating. When the water pump cannot do its job properly, then the coolant cannot circulate and cool down in order to return to the water pump, so the hot coolant will evaporate.
If you see steam coming from the front of the vehicle, stop the vehicle to the side of the road immediately. Driving with an overheated engine can cause damage that cannot be repaired.
Although the cause of an overheated engine may be something other than a bad water pump, such as a bad radiator or thermostat, the result is the same: a bad engine from overheating.
Therefore, if it is not a small leak with the ability to add more coolant, have the car towed to a mechanic to be repaired.
#3. Strange Sounds (whining, buzzing, squealing).
A whining, buzzing, or squealing engine could indicate a loose accessory belt, caused either by a loose pulley or bearings which are worn out. If the bearings are in the water pump, it will require replacement.
One of the leading causes of premature water hoses failure is over tensioned accessory belts. If you are replacing a water pump yourself, it is highly recommended you buy a belt tension gauge to assure the tension is properly set to spec.
If you hear a whining noise that implores you to turn down the volume as it increases with your cars accelerations, it should be inspected immediately.
#4. Fluid Leaks.
If you notice bright green or orange fluid pooling below the front of your car after its been parked for a few hours, it may be coolant. Discoloration can be caused when the gaskets and seals inside a water pump wear out, crack, or feel to fail completely.
Even if a puddle is not visible, it is still a good idea to take a look at the water pump itself, especially if you are seeing other indications, to ensure it does not appear to have more debris on it compared to other parts in the engine.
In addition to a pool of fluid, a slow discharge of coolant can dry up on the outside of the water pump and solidify, or lead to rust/corrosion (indicated by “pitting” of metal).
Aside from puddles, some leaks will only occur when the pump is turning (i.e. when the vehicle engine is running), and not after the car has been shut off. It would be incorrect to attribute the latter leakage to a failure of the water pump; it could be due to a separate problem, such as a malfunctioning radiator.
If you notice a leak occurring from the weep hole in the water pump, it could indicate a problem with the seal, as it is designed to keep contamination of oil in the bearings separated from coolant, and vice versa. The weep hole droppage will cease once the engine shuts off.
#5. Readings/fluctuation of the temperature gauge.
If the cooling system is functioning correctly, it will keep the temperature gauge within normal limits at all times. If the water pump is failing or has failed, the needle on the temperature gauge may fluctuate, working back and forth from the normal position to the hot position and vice versa.
An above failure could also be caused by a failing radiator, if you are experiencing above readings, both components should be repaired before further driving the vehicle.
Another possible reason for gauge fluctuations, would be an air bubble. Whether around the temperature sensor, it could be causing inaccurate readings of the coolant temperature.
Cost of Water Pump Replacement
Replacing the water pump varies greatly depending on the size, make and year of your car, but estimates range from $310-$730 all in. If you have a big SUV, higher end car, or os paying dealership prices, expect to pay more.
The parts themselves (water pump and other parts) will cost about $70-$400. Labor will cost you approximately $240-$330 (based on a standard rate of $80-$110/hour) . Average time to replace a water pump is three hours.
If you choose to purchase the water pump yourself and provide it to the mechanic, you could pay less, but make sure you buy from a reputable source!
Your vehicle’s make and model will have a significant impact on your total cost. Location can increase the price as taxes and fees vary by area.
While the cost of replacing the water pump can be substantial, it is a big ticket item for your car compared to replacing an engine. A vehicle should not be driven until repairs have been completed.
If you can’t remember when your water pump was last replaced, have it done soon as it is an inexpensive insurance policy for your engine. Many local shops will replace the water pump at the same time as doing the timing belt, while they have access.
Replacement Process
Water pump replacement is best left to a professional unless you have a fair amount of mechanical experience, as this usually takes a lot of witches fingers, blood, sweat and tears.
In short, the existing coolant is drained, then parts have to be taken off (ie, timing chain or belt) to reach the water pump. Next, you have to inspect the water pump, hoses, and other related part,s and you may need to replace them as well.
You should also replace the thermostat and a new or newish radiator cap too, along with any gaskets/seals that may have come off during disassembly. If the radiator is old and leaking or even shows signs of age, replace it.
Then you replace all of the components back again in reverse order (including refilling the cooling system), and test it for leaks. Following a test drive, you should be sure that your new water pump is working properly with no leaks.
While the mechanic is removing parts and obstructing access to the water pump, there may be other components that may need replacing at the same time (ie timing belt or chain), so always ask for a quote before giving the nod to any additional work.
Warning!
Remember that coolant (antifreeze) is hot and under extreme pressure after the vehicle is running and for several hours after it is shut off!
Do not remove your radiator cap or touch anything in the cooling system until the engine and cooling system have cooled off completely.