mechanic handling a water pump

Why does a car need an electric water pump?

Back to Info & Advice/in /by

All there is to know about water pumps for cars

Did you know that your car’s water pump is responsible for circulating coolant around your engine’s cooling system? This is an extremely important feature. Without circulating coolant, your engine produces too much heat, leading to malfunctions and potentially irreparable damage.

But why does a car need an electric water pump? Now that we’ve established how important water pumps are, we ask – which kind do you have? Mechanical or electric?

The bet is if you have an older vehicle, you’ll have a mechanical water pump. Modern vehicles typically have electric water pumps due to the range of performance benefits they have.

So, why is electric better? Before we get to the juicy part, let’s take a look at how water pumps do their job.

Natrad has a huge range of water pumps ready for installation into your vehicle. If you’re in the market for industry-leading parts and unbeatable service, give us a call.

How do water pumps work?

First off, we must understand the fundamental function of a water pump. Whether it is mechanical or electric, it is responsible for creating the motion to circulate coolant around the cooling system. Without the circling of coolant, the engine would overheat, leaving your car undriveable and likely many other engine bay parts damaged.

But how does this happen? Depending on whether the pump is mechanical or electric, it will become engaged, either via controller (electric) or while connected to engine power via crankshaft (mechanical). As the engine speeds up or down, or as the sensor detects heat, the pump pushes coolant around the system and radiator hoses, starting from the engine block, to the cylinder heads, to the radiator and back. The coolant can pass by other parts of the system, such as the blower motor in the HVAC system if the heater in the cabin is turned on.

The water pump is also connected to the radiator fan clutch, which contributes to engine cooling.

Mechanical vs electric

Now that you’ve grasped the basics, the next step is to differentiate a mechanical and electric water pump.

A mechanical water pump is driven by a belt pulley, typically the timing belt or engine belt depending on its location within the engine bay. Sometimes water pumps are placed externally in their housing rather than directly flanged to the engine. This dictates which belt they are connected to. Since belt driven water pumps are directly connected to the engine, this is where they get their power.

Depending on the engine speed, the water pump spins accordingly, which can sap precious horsepower and fuel efficiency. It can also lead to excessive or inadequate cooling. An example of this is on the highway where the engine speed is high, and therefore so is the speed of the water pump. However, the engine requires less cooling as there is a lot of airflow, so the high water pump speed leads to excessive cooling. Meaning, you waste engine power unnecessarily.

Main benefits: 

  • Powerful coolant flow due to connection to the engine

An electric water pump is far more in tune with your engine’s specific cooling needs. By utilizing a controller, it can determine how much coolant circulates through the engine at given temperature ranges and maintain a target temperature. This prevents inadequate or excessive cooling. While running on battery power, it also doesn’t derive it’s power directly from the engine. This means your fuel economy and horsepower is safe.

It has also been found to last longer. Without exposure to engine harmonics, the lack of exposure to such stresses can expand its life span. The only downside is that coolant flow may not be as strong, since it’s powered by electricity and not mechanical forces.

Main benefits:

  • Temperature sensitivity
  • Lighter
  • Longer lifespan
  • No negative impact on horsepower or fuel economy

Failing water pumps: signs and symptoms

Repairs are a short-term solution for water pumps and should definitely be replaced for long-term functionality. Replacing your water pump usually means changing the timing belt if you have a mechanical one. This can be a big job, and if you can, is best to avoid water pump or belt failure prior to service. Preventative servicing is usually the way to go, but if you notice these signs you should jump onto it immediately:

  • Water pump corrosion
  • Engine overheating
  • Whining noises (loose pulley)
  • Coolant leak (leaking water pump)
  • Worn belt
  • Weep hole leak
  • Deposit build up
  • Cavitation (formation of bubbles)
  • Damaged shaft or bearing
  • Coolant contamination

If you’re in need of a replacement water pump, Natrad can help. With a wide range of electric and mechanical pumps to suit your vehicle, nip into your local Natrad today for excellent service.