The water pump is a key part of an automotive cooling system. When it goes bad, you have some big problems, so knowing what a bad water pump will produce is useful.
We cover some of the most common bad water pump symptoms, its location and function. We will discuss how to test a water pump, costs for replacement or repair, and answer some frequently asked question.
What’s The Function Of A Water Pump?
The water pump pushes coolant from the radiator, through the motor and back to the radiator in a continuous cycle. When a water pump works properly, an engine will operate at a steady temperature.
As coolant makes it’s way through the engine, it absorbs heat. When it returns, the coolant passes through the radiator to release heat and re-enter the engine at lower temperatures. Without the cooldown process, the engine gets overheated.
In most vehicles, the engine drives the belt that turns the water pump. The centrifugal force of the water pump’s vanes and shaft draws coolant into the pump.
Once the coolant enters, the water pump forces coolant against the outer walls of the pump and down a drain into the engine block. Then, it will return through the cylinder heads and back to the radiator where the cycle starts all over again.
Symptoms Of A Bad Water Pump
When the water pump fails, coolant will leak from it, and the engine will overheat. A squealing noise or white smoke could also come from the engine.
In some cases, you will also have an unstable engine temperature, which could make diagnosing the problem more difficult.
Carefully investigate these possibilities to see if you probably have a failing water pump.
#1. Leaking Coolant.
Coolant leaks can occur for many reasons, and while a bad water pump can be the culprit, it’s not always the most likely cause. If the coolant is leaking from the front of the engine, the pump is something to check if you suspect a leak. Either the gasket around the water pump is leaking or the seal on its shaft is leaking.
When the leak is small, it may not even leak onto the ground below, but rather, it drips on the front of the engine. With heat, the coolant dries up quickly. When this is the case, you will notice a white trail of dried coolant.
Either way, you will want to address if there is a coolant leak sooner rather than later. If too much leaks out, the engine could overheat and cause irreversible damage to the motor.
#2. Overheating Engine.
The coolant keeps the engine temp at a normal operating temp. If the gauge gets high, and the engine overheats, the coolant is not working properly.
One reason could be a failing water pump. An air pocket in the coolant system or contaminated fluid could also be the problem. Mechanical failure plays a role too, as with a failed thermostat.
If the water pump was the problem, there could have been many things that occurred. It could have just been old or worn out. Or the impeller may have been broken due to cold weather or debris getting to it.
Either way, if you were to continue driving with an overheating engine, it will lead to catastrophic failure in some form, whether it was a blown head gasket, a seized engine, or warped cylinder head.
#3. Squealing Noise.
When a water pump fails, it will typically squeal or chirp distinctly and can be heard from the front of the engine and similar to serpentine belt noise. A failing water pump is generating resistance which causes the belt to slip on the pulley which makes the noise.
It is usually the result of a worn shaft bearing. A noise is too late. Your water pump is failing. Consider this a warning and start making arrangements to resolve the situation.
#4. White Smoke From Engine.
If steam or white smoke is coming from the radiator, chances are good that the engine is overheating, possibly from a defective water pump, or because of an inferior radiator cap that is leaking coolant.
Regardless of the cause of the steam or smoke, you should pull the car over immediately. It is never a good idea to drive with an engine that is overheating, even a short distance, because it doesn’t take long to damage an engine in a way that makes it beyond repair and a replacement necessary.
#5. Unstable Engine Temperature.
You may see the engine temperature fluctuating between normal and hot, although this is less common. If the coolant cannot circulate to reduce the temperature, you can expect your engine will start running hot.
It may go down a little if you’re driving at highway speeds and lots of air is circulating. In any case, if the temperature gauge ever gets into the danger zone, have the cooling system inspected.
Where Is The Water Pump Located?
Water pumps are typically located near a drive belt or serpentine belt. This makes the water pump easier to find because it is typically at the front of the motor. If the water pump is driven off the timing belt, it can be a bit harder because it may require you to remove other parts or covers to see the water pump.
The best and only way to know for sure is to either have a service manual or look up a diagram on the internet. Knowing the location of the water pump can help you decide if you want to replace it yourself or take it to a shop.
How Do You Test The Water Pump?
If the temperature gauge rises or if you hear strange sounds from the area of the water pump, pull over and try to find out what is happening. Some of the diagnosis isn’t too difficult to diagnose at home with some simple tools.
Here are some things to consider.
- Park on level ground.
- Turn the engine off. It is best for working with the cooling system when the engine is cooled off.
- Inspect the water pump pulley. Wiggle the pump pulley back and forth lightly. You should see no movement whatsoever. If there is any movement at all, you may need a new pump.
- Inspect for leaks in the system. If you can locate the spot of leakage, you will have an easier time determining if the water pump is the cause. Check for leaks coming from the water pump housing or around the gasket. Replace pump if leaking.
- Inspect the coolant reservoir. If there is a leak, the level of coolant will be lower. Leaks can also happen at the water pump gasket from contamination of the fluid, particularly if you don’t do a flush on the coolant occasionally.
Sometimes, you won’t be able to inspect the water pump without taking off the timing cover. This can be a more complicated operation most home mechanics aren’t equipped for.
As professional technicians, our advice is always to call your local repair shop if it feels like something you don’t have complete confidence in accomplishing. You will always rather pay a little more for the repair than have another component break.
How Much Does It Cost To Replace A Water Pump?
The average water pump replacement cost is $550 to $900. The parts will cost $350 to $500, and labor can be an additional $200 to $350. Cost can go much higher depending on location of the water pump and the type of vehicle you drive.
For example, sometimes it is recommended to change the water pump pulley, timing belt, or serpentine belt at the same time; any of these procedures will add more costs to your repair.
FAQs.
How long will it take to put a water pump in?
This will depend on how easy you can get to the water pump. If it’s a basic replacement, you might only need to spend two hours installing a new water pump.
If there are other parts involved that need to be removed to get to the water pump, you could easily spend all day replacing it.
Can I drive with a bad water pump?
Yes, but if you know the water pump is bad, you should stop driving. The engine is guaranteed to overheat, and once it does, there’s virtually guaranteed permanent damage.
It doesn’t take long to overheat either. It might even only take a few minutes of driving to result in a warped cylinder head, blown head gasket or seized engine.
How long can I drive with a bad water pump?
You shouldn’t be driving it at all once you know the water pump is bad. The water pump won’t keep the coolant circulating, which means the engine won’t be cool, and it will overheat, potentially causing extensive enough damage to necessitate a motor replacement.
What makes a water pump bad?
Most of the time, water pumps simply go bad due to old age. If a pump has seen a lot of use, it’s going to go bad eventually. Additionally, the impeller will go bad, or one of the bearings can go bad.
A gasket or seal can also go bad, allowing coolant to leak. If the water pump is going bad, it can put more pressure on the drive belt causing additional issues.
What does a faulty water pump sound like?
A water pump failure usually results in a chirping or squealing noise coming from the front of the engine. It is similar to the noise the serpentine belt sometimes makes, and the noise may just be from the added strain on the drive belt because of the water pump pulley.
There are some parts on a car that should never be ignored as failing, and the water pump is one of those parts. The water pump is essential to keeping the engine at a normal operating temperature, so you want to replace the water pump at the first sign of failure. Although replacing the water pump may not be thrifty, it will certainly be less expensive than replacing the engine.
If you’d like to drive the car for more miles, it is advisable for you to stop driving and replace the water pump. If you are unsure how to replace the water pump, your car’s service manual should explain how to do it, or you can take it to a repair shop.