Can a bad water pump cause no heat? Let’s see the answer

When we think of car problems, the most common parts that come to mind are the engine, gearbox, and other sophisticated car parts. We forget about other less talked about but very important parts like the water pump.

It is responsible for regulating temperatures around the various engine parts. Without it, the engine will overheat or freeze. Some of the parts most susceptible to damage include the gasket, the cylinder heads, and pistons, these are expensive to repair.

There were a lot of situations when drivers often asked me: can a bad water pump cause no heat?

The answer to this question is yes, if the part responsible for circulating the coolant around the engine is not working then no heat is an inevitable result.

What Causes Water Pumps To Fail?

A water pump can fail due to old age. If a water pump has delivered over 1.65 million liters of water, experts believe it has every right to retire.

There are cases, however, of water pumps failing before their expected lifetime expires. There are myriad reasons that can be attributed to this, we will discuss the most common.

1. A Worn Out Seal

The water pump holds the coolant during its lifetime and there is a likelihood that it will leak. There is a seal around the water pump housing that prevents the leaking but it sometimes cannot hold. The seal also protects the coolant from excess air.

The seal leaks due to several reasons: a corrosive coolant, poor installation, and if the car is left unattended for too long.

The leaking coolant is not good but the real problem is the air that gets in through the leak. The introduction of oxygen in the pump can cause corrosion or negate the pump efficiency.

If the air pockets fill the engine blocks, you can expect it to overheat or at least malfunction.

To protect your engine, you are advised to insist that the mechanic checks the water pump seal whenever you go for servicing.

2. Defective Drive Pulley

The water pump has a part called the drive pulley. If it gets loose or wobbling you can expect worse things ahead. Whenever this part gets loose, it vibrates and eventually wears out the pulley bearings. This will result in the water pump failing.

The vibration might not affect the water pump directly all the time. It sometimes causes the impeller to lose balance-this will affect the water pump too.

Whenever you replace the water pump, do not spare the drive pulley. Things are easier these days though-the water pumps and drive pulley to come conjoined.

3. Broken Or Cracked Belt

Mechanics rarely inspect this very important part-the water pump pulley belt. It must be checked for cracks, breakages, or wear.

The tightness is also an important aspect to worry about, it can easily get loose. You should ensure the belt is neither too tight nor too loose.

Either will result in the water pump, not working-a nonoperational water pump, and a defective water pump having the same effect on the system.

A loose belt can be tightened but an over-tightened one needs replacement. Continuous use of an over-tightened belt will cause the casting to fail.

4. Corrosion Effect

Mechanics have a hard time explaining this to car owners but the effect corrosion has on water pumps is huge. Very many water pumps have been written off due to mere corrosion.

The corrosion occurs when the coolant is replaced with a tap water-laden coolant. You are required to only use distilled water. Another cause of corrosion in the cooling system is poor maintenance.

Corrosion is difficult to detect unless it has already claimed victims. Most of the time, corrosion is only noticed after the impellers begin to malfunction. If the damage is extensive, the water pump will be leaking already.

Ensure the water added to the cooling system is distilled and regularly check the coolant level.

Does The Water Pump Control Heat?

Yes, it might be as important as the engine but the water pump plays a role in regulating the heat in the engine. It pushes the coolant that moves around the engine parts maintaining adequate temperatures.

How Do I Know If My Thermostat Or Water Pump Is Bad?

Having an understanding of the various signs of a failing water pump can help you detect the problem before it gets out of hand. The damages bad water pumps cause are sometimes irreversible.

A leak.

Most of the time, a damaged water pump will leak the coolant. You will notice it on the floor of your garage or parking lot after parking your car for some time. This is caused by a worn-out seal.

If you suspect your water pump is failing, lookout for a blue, pink, or green liquid on the ground before driving out.


Rust is a major enemy of the water pump. It builds up, weakens the pump, and eventually damages it. Rust results from the use of sub-par coolants, or air getting into the pump-ensure there are no leaks and that the pressure cap is efficient enough.

The rust can be detected by simple observation of the area around the water pump for any signs of corrosion.


When the water pump belt gets loose, it causes strange and high-pitched sounds around the engine’s front. Whenever you hear these noises, make time to see the mechanic.

Over Heating

The water pump is responsible for heat regulation. If the car overheats, there is a chance the water pump has a problem.

How Do I Check If My Water Pump Is Working Without Removing It?

  • Place a cardboard piece under the car water pump and observe for a leaked coolant after some time (overnight).
  • Listen for odd sounds coming from the engine area.
  • The temperature warning is a sign of a faulty water pump.
  • If the coolant light is on, that’s a bad sign.

What Does A Bad Water Pump Sound Like?

The sounds are usually characterized by whining, squeaking, and grinding. Be advised, not all defective water pumps make sounds.

Can A Water Pump Go Bad Without Leaking?

Leaking is only one of the multiple signs of a failed water pump. The pump can fail due to other reasons like rust caused by air getting in through a defective pressure cap. As you inspect, do not limit yourself to leaking.

How Long Can You Drive With A Bad Water Pump?

You are advised to limit the distance to the minimum. The car will drive but there is a high risk of overheating because the car is not cooling as expected. This can cause major engine damage.

Bottom Line

As we care for the engine and other “vital” parts, let’s not forget the water pump. It plays an important role in keeping our vehicles on the road and neglecting it can be costly.

Regularly check it out and learn to take heat warnings on your dashboard more seriously.

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