Engines with electric auxiliary pumps become more efficient, as they generate less excess heat and oil consumption. Even though not all vehicles have one yet, these pumps are growingly popular in modern, low-emission and high-output engines that have to run within a small temperature range in order to maintain their efficiency.

The usefulness of an auxiliary electric water pump

So, what is an auxiliary water pump? It is a secondary pump that plays a crucial role in maintaining engine efficiency and passenger comfort. These pumps can send hot coolant into the heater core regardless of the engine’s RPMs, providing hot/cold air to the cabin even when the engine is idling or off. The auxiliary coolant pump can continue to operate while the car has stopped, allowing coolant to circulate and fully dissipate the heat from the supercharger.

This type of water pump is essential for passenger comfort, since it allows for sufficient heating even when passengers are driving in traffic or at low RPM. Also, many modern cars use this second pump to allow you to use the air condition for a period while the engine is off. 

Note that unlike the main water pump, this one is not running all the time. The electronic control unit will regulate the auxiliary pump according to the needs of the moment.

To sum up, some of its unique advantages include:

• Facilitates demand-driven cooling of the vehicle.
• Saves on fuel.
• Enhances passenger comfort.
• Is efficient in cooling down power train components.
• Reduces emissions.

Auxiliary electric water pump diagram

Understanding the auxiliary electric water pump diagram is essential to grasp how this component integrates into the vehicle’s cooling system. This pump is typically located near the heater core or within the engine bay and operates as part of the broader coolant circulation system.

A standard auxiliary electric water pump diagram includes the following key components:

• Main coolant lines – Transport coolant throughout the engine.
• Heater core – Receives heated coolant to provide warmth to the cabin.
• Bypass hose – Allows the auxiliary pump to circulate coolant independently.
• Electronic Control Unit (ECU) – Regulates pump operation based on temperature and vehicle conditions.
• Electrical connections – Power and control the auxiliary water pump motor.

The pump activates based on inputs from the BCM (Body Control Module), ensuring coolant circulation even when the engine is off or idling. This contributes to passenger comfort, fuel efficiency, and optimal thermal management of powertrain components.

For a detailed diagram specific to your vehicle, always refer to the manufacturer’s service manual.

Related content: Peculiarities of an auxiliary water pump

Reasons to change your auxiliary electric water pump

The main reason these pumps fail is the electric motor’s natural age and wear. If this does happen, then the heater core will not be able to heat up and replacement will be necessary.

Within age and wear, there are 5 common ways in which electric auxiliary water pumps can fail:

• Weep hole is leaking coolant, indicating that the dynamic seal has failed. 
• The water pump leaking into the engine, making the oil milky and thin.
• Pump’s impeller fails and makes a chirping noise as it contacts the housing.
• The galleries in the water pump become plugged from sludge build-up.
• Electric motor fails due to a short in the wiring, making it inoperable.

Potential complications

A failed auxiliary water pump will almost never cause the vehicle to overheat. However, if inoperative, you might notice some of the following situations during driving:

• No warm air coming from the heater: since its primary job is to supply hot coolant to the heater core, the first symptom of a problem with this component would be no hot air blowing from the heater.
• Heater shows fluctuating heat: the temperature inside the vehicle is increasing or decreasing based on the driving mode, especially if there is a noticeable temperature decrease when the engine is idling.
• Windows defrost is not working: when windows fog up, the defrost mode is in charge of blowing warm air onto the windshield for clear vision. If the pump is failing, the windows will not defrost rather quickly.
• High-pitched buzzing sound: coming from under your dashboard, this might happen if there is an electrical short in the wiring, making the pump run faster than it should or continue to run after the engine is off.

How to replace an electric auxiliary water pump step by step

Once you have verified the condition of the electric auxiliary water pump and confirm its need for replacement, make sure to follow these steps one by one for an optimal replacement. Remember to always consider individual instructions proposed by the vehicle’s owner manual.  

Auxiliary water pump replacement step-by-step:

1. Drain the coolant from the system.
2. Remove any interfering parts, if necessary.
3. Disconnect the auxiliary water pump connector.
4. Remove all the hoses connected to the pump.
5. Remove all the mounting bolts and the auxiliary water pump.
6. Install the new auxiliary water pump and tighten the bolts.
7. Connect again the hoses back.
8. Install all previously removed parts in the reverse order.
9. Fill up the cooling system with indicated coolant to the required level.
10. Bleed coolant system according to the service manual.
11. Check coolant system for leaks.

And that’s it! You are done! 

Remember to always test drive the vehicle by driving it around and monitoring the cooling temperature!

Discover our range extension of Auxiliary Electric Water Pumps

The importance of proper selection of auxiliary electric water pumps

A good quality electric auxiliary water pump will determine the time span of an optimal coolant system and performance in any modern vehicle. These pumps are not only used to make modern engines efficient but have enabled the cooling of batteries in hybrid and electric vehicles.

With a complete range of auxiliary water pumps of more than 60 references, DOLZ offers its customers the best solutions thanks to personalized attention and the latest technology in the manufacture of water pumps for the aftermarket sector.

If you are looking for top-tier auxiliary electric water pumps, contact us and we will provide you with the information and support you need.

La entrada When and how to install an auxiliary electric water pump se publicó primero en Industrias Dolz.

In today’s article we talk about the top 5 mistakes in the installation of a water pump and how to effectively install this key element of the cooling system.

Keep learning: Understanding the water pump drive: Exploring its location and operation

Installing a water pump: Mistakes

1. Cooling System Preparation

One of the main and often overlooked problems is in the preparation of the system through which the water pump will circulate the coolant.

Before installing a water pump it will be especially important to flush, drain and refill the cooling system with the OE (original equipment) specified coolant mix. On the contrary, the correct operation of the new water pump would be jeopardized.

Dolz Tip: When preparing the cooling system, if you notice that the old coolant is very dirty, it is advisable to check the thermostat and replace it if necessary. If you’re unsure how to check thermostat car, ensure you follow proper steps, including inspecting the thermostat for signs of malfunction and verifying coolant flow behavior.

2. Improper mix of coolant and water

Another common error is found in contamination caused by the incorrect mix of coolant and water or its improper use. Contaminated or improperly mixed coolant can cause corrosion problems, the dreaded cavitation, and cause leaks between the two contact faces of the water pump’s dynamic seal.

When choosing the right coolant, it is essential to check the expiration date and follow the vehicle manufacturer’s recommendations, as each individual engine is made from different materials and has specific needs.

3. Incorrect use of sealing paste

The use of sealing paste in the water pump is only necessary in those that are supplied without a gasket. Otherwise, if we add sealant when it is not needed, we will cause any particle of sealing paste that circulates through the cooling circuit coming from the pump gasket, which may affect the functionality of the dynamic seal, preventing the correct sealing function and causing a failure premature of it.

Incorrect use of sealing paste will directly affect the life expectancy of the water pump. Therefore, unless specified or referenced without a gasket, avoid the use of sealants.

4. Water pump dry rotation

Another mistake to avoid during installation is dry rotation of the water pump.

When refilling the cooling circuit after replacing the water pump, many manufacturers recommend that the pump be turned by hand until it is full. This fine-tuning of the pump can reduce the possibility of loss of the “mechanical” seal since the coolant liquid reaches the component of the mechanical seal creating a film that will prevent its spillage.

Otherwise, if the pump runs dry, it will cause damage to the seal, which may lead to premature leaks or squeaking noise in the water pump.

5. Water pump and timing belt

One of the most common mistakes is to overlook the distribution when we are doing the installation of the new water pump. The water pump is driven by the belt transmission system, which means that combining the replacement of both systems improves the quality and the safety of the process, which is why it is a highly recommended practice.

Previously the replacement of these two components was carried out separately, but nowadays it is more and more common to carry out this operation at the same time. This allows better vehicle performance and longer average lifespan of the water pump.

If the timing belt and other related items are installed incorrectly, this will directly affect the performance of the water pump.

Relating Content: Discovering the main water pump components

Discover Dolz’s water pump range

We manufacture more than 5.5 million units per year over a range which comprises:

• Water pumps for passenger cars
• Water pumps for industrial vehicles
• Auxiliary electric water pumps
• Variable water pumps
• Electric water pumps

All our range has the ISO 9001:2015 certification, which means quality 100% tested. A process as simple as it is fundamental and for which, among many other factors, DOLZ water pumps are the pumps with the highest quality on the market.

Main characteristics of the range

• The DOLZ range is made of 1300 references, among which 990 for cars applications & 18% only for Asian applications,
• 95% coverage of the European car parc.
• 95% of the DOLZ range includes a Silicon Carbide Dynamic Seal, that guarantees optimum tightness and durability of the water pump,
• Water pumps designed according to OE specifications,
• Automatized manufacturing process that guarantees an excellent quality.

All of them have 100% cast aluminum material, resistant to wear and OE equivalent, always following the highest standards.

At DOLZ, we have been an expert manufacturer of water pumps since 1934. If you would like to find out more about our range of water pumps and other Dolz product lines, contact us!

La entrada Top 5 mistakes to avoid when installing the water pump se publicó primero en Industrias Dolz.

Heavy vehicles such as trucks or industrial vehicles involve large engines and therefore generate a large amount of heat. That is why the cooling system is considered a key element for good engine performance. Overheating can increase the risk of engine damage, so it is essential to ensure that the engine does not experience additional stress due to extremely high temperatures.

Keep reading to learn more about electromagnetic truck water pumps, their variable operation and how they differ from traditional mechanical water pumps.

What is an electromagnetic water pump?

There are different ways to regulate the coolant, some of them are carried out by an electro hydraulic actuator, or a belt drive, also by electrical activation on the water pump back housing (thermostat) or also by an electromagnetic coupling.

In relation to the last one mentioned, the use of this electromagnetic technology has spread to form part of systems such as vehicle air conditioning or engine cooling system, meeting the growing demands for efficiency and flexibility in engine performance.

A key component of any water pump is the impeller, responsible for moving the coolant through the system. But what is impeller in pump technology? The impeller is a rotating component with vanes or blades designed to increase fluid pressure and flow. In an electromagnetic water pump, the impeller’s operation is optimized by the electromagnetic clutch, adjusting the coolant flow based on engine demand.

The main difference between a mechanical water pump and one that has the EM (electromagnetic) clutch is that this electromagnetic clutch system can automatically adjust output flow of the water pump more meets the demand of motor. On the other hand, the traditional water pump will circulate the coolant in a fixed and constant way because its speed is directly connected to the speed of the engine.

How does the electromagnetic clutch work? 

In an electromagnetic clutch, the pulley (rotor) is independent of impeller. The connection between both elements is achieved by pressing two friction elements using an electromagnet.

When this electromagnet is activated, the clutch engages, and both the rotor and the impeller rotate together. Without current, a spring separates the friction elements leaving the rotor free of the system. Clutch system control is performed by the engine control unit (ECU) using thermal sensors located on the engine.

To guarantee a minimum flow of the pump when the electromagnetic clutch is deactivated, a second magnetic clutch is fixed to the rotor. This second clutch does not guarantee joint rotation between both components, but it guarantees a 50% and 60% of the flow between them when there is a friction coupling.

In most situations, this flow is enough to keep the engine properly cooled and to have this type of clutch, which has no friction or contact between the rotor and the impeller, significantly reducing power consumption and besides fuel consumption. Only in some situations as per example high outside temperatures, a 100% flow is necessary and, in those cases, the electromagnet will activate to generate a total coupling by friction.

For all the above considerations, its main advantages are:

1. 1. Reduces fuel consumption.
   2. Provides greater flexibility thermal management.
   3. Reduces system inertia and increases tolerance to changes in revolutions.

• Guarantees minimum flow for normal circuit operation if an electrical system failure occurs.

*V501 Dolz electromagnetic water pump for truck

Related content: Truck water pump: How to select the correct one?

Main components of the EM clutch

• The rotor, the pulley, the element that is in contact with the belt fixed to the water pump.
• The static friction ring, attached to the rotor, and the spring-loaded secondary friction ring, engaged to the impeller through the inner shaft.
• The electromagnet, attached to the water pump, which acts on the spring-loaded friction ring and engages it on the static ring. And then, there is a secondary magnetic clutch magnets.
• The secondary clutch armature ring, over the magnets.
• Heat dissipation system

Dolz Electromagnetic Water Pump

Industrias Dolz has been manufacturing and distributing high-quality water pumps for passenger cars, commercial & industrial vehicles since 1934.

Among the strengths of Dolz water pumps are:

• Full in-house production …All in Dolz
• Self-lubricating silicon carbide (SiC) seals, with HNBR rubbers and synthetic graphite contact rings to increase durability and guarantee performance.
• OE equivalent.
• ISO 9001:2015 Quality Management System
• All water pumps are supplied with the necessary fittings/gaskets.

Dolz has a manufacturing plant built on an aera of 25,000 square meters focused on innovation and market demands, automation and robotization in production processes and logistics efficiency. It manufactures more than 100,000 automotive water pumps per week and has a permanent stock of more than half a million water pumps.

Keep reading: …All in Dolz. In-house production end to end.

Contact to discover more about our full range of electromagnetic water pumps and other Dolz product lines. 

La entrada Electromagnetic water pumps for truck se publicó primero en Industrias Dolz.

Where a car’s engine is housed, there are several systems in charge of making it work as it should. Among them, the cooling system where the engine water pump is a key component, helps to lower the excessive temperature of the engine dissipating excess heat.

Find out everything you need to know about the water pump, what role it plays in your engine, and how to choose the correct water pump to ensure efficient driving.

What does the engine water pump do?

Simply put, an engine water pump is at the heart of an engine’s cooling system (without it, the system would not be able to fulfill its purpose). Thanks to the water pump, which operates together with the thermostat and the radiator, it is ensured that the engine block maintains the correct temperature, preventing overheating and optimally completing combustion.

As we’ve seen, the job of the engine water pump is to circulate coolant that absorbs heat, the full circuit being receiving coolant from the radiator and sending it through hoses to the engine. Once it reaches it, the coolant liquid absorbs heat and goes back to the radiator, where it’s cooled so that the cycle can start again. All this allows the combustion engine to reach its intended service temperature as soon as possible and maintain optimal conditions in different load situations.

Thus, the water pump is essential for the proper functioning and durability of the cooling system and the overall operation of the engine. It’s important to ensure that this system has the best possible quality and therefore contributes to good thermal management of the engine.

Basic parts of an engine water pump

A water pump consists of several key components, each playing a crucial role in ensuring the efficient circulation of coolant throughout the engine. Below are the basic parts of water pump and their function:

• Impeller: It is a rotor that increases the pressure and flow of liquid inside a water pump. The impeller is the heart of a water pump, and without it, the entire system can fail. There are different impeller types, each designed for specific applications to optimize efficiency and durability.
• Housing: responsible for protecting the water pump from external damage, as well as preventing the coolant from leaking out of the circuit and damaging the engine. They can be made from aluminum, cast iron or steel.
• Spindle bearing: it represents the mechanical support enabling the shaft to move continuously and steadily. It receives the turning force from the pulley and transfers it to the next component in line, which is the impeller. 
• Hub or Pulley: it acts as the power source for the impeller, thus generating the rotation forces needed to the engine water pump to function.
• Seal: it’s in charge of preventing leakages and avoiding bearings from being contaminated. It plays an important role in keeping the water pump intact.

Related content: Discover the main parts of a car engine (and its functions)

The relationship between the water pump and the engine

The purpose of the water pump is to counteract the increased heat produced by the engine. It would not be possible to dissipate the excess heat generated by combustion or to cool it faster and more efficiently without a water pump in the cooling circuit.

All in all, the performance of the different parts of the engine and the water pump is intrinsically connected: the power consumption of the water pump thereby increases in line with the engine speed. In fact, if your water pump stops working, your engine could fail.

Understanding the engine cooling system 

A typical engine cooling system comprises the following components: 

• Radiator, which acts as a sort of heat exchanger through the use of many fine tubes in charge of receiving and cooling the liquid sent from the engine. Radiators pass excess heat into an airstream, effectively cooling the liquid that is then returned to flow back into the channels. 
• Water pump in charge of circulating coolant. As we’ve seen, it’s driven by pulley and belts from engine crankshafts. It will send coolant down through the radiator, assisting in the circulation of the coolant.
• Thermostat, in charge of adjusting the level of coolant that will later circulate into radiator.
• Fans, driven by belts, it is responsible for pulling out air through the radiator.
• Hoses, where the coolant circulates.
• Coolant, the liquid in charge of absorbing heat from the engine and circulating through the whole cooling system. It is highly recommended to always use the antifreeze that’s recommended by your car manufacturer and never use water.

Keep reading: Engine cooling system: how it works and main components

Expert manufacturers of engine water pumps

One consideration to keep in mind after what we have seen in this post is that the process of choosing the right water pump brand can make a difference in engine efficiency and durability.

At Dolz we produce and distribute quality water pumps for passenger cars and industrial vehicles as part of the independent aftermarket. 

As such, we’re in charge of manufacturing more than 5.5 million water pump units per year. Our water pump catalogue includes 1,300 references: 900 for passenger cars (of which 230 are specifically for Asian applications, and another 200 for hybrid and gasoline cars) and 400 for trucks (trucks, vans, tractors, 4×4, 4×5, 4×6, 4×7, 4×8, 4×9, marine applications, forklifts, industrial engines).

Get in touch with us and discover our full range of products. 

La entrada Engine water pump: what does it do and why it’s a key component se publicó primero en Industrias Dolz.

Water pumps have a long service interval, but this often means that car owners underestimate the eventual need for a new water pump. Although water pumps wear over time, certain negligent factors are mostly responsible for speeding up this process.

Water pumps and timing belts have similar lifespans. Which is why Dolz highly recommends replacing both at the same time. This not only ensures efficient and safe maintenance, but it also incurs labour costs savings and a shorter period of non-use. 

How long does a car water pump last?

When considering a durable and reliable water pump, there are two factors that play the biggest role in ensuring a water pump’s long life: 

1. Water pump fitting and quality. 
2. Cooling system maintenance.

Go deeper: Failing car water pump: Signs

Specific water pump lifespans vary depending on the vehicle’s model and on its type of cooling system. Firstly, it is highly advisable to find a reliable partner before having to replace the last water pump, and secondly, to follow the recommendations specified in the car owner’s manual when installing the water pump.

Furthermore, the urge for a brand-new water pump will largely depend on driver practices throughout the years. If preventive maintenance and thorough care of the vehicle’s cooling system are taken seriously, a quality water pump can last up to 100.000 miles, again, depending on the model.

Is a new water pump needed? – Signs

Among the most common causes of water pump damage are leaks, improper use of sealant, damage from improper use of coolant causing cavitation damage, and corrosion. Most of the wear occurs inside the unit, which is why oftenly it cannot be seen until opened.

Keep reading: 3 reasons to replace both the timing belt and the water pump at the same time

Regular maintenance should include the dismantling of the water pump to accurately check for wear at central parts. However, there are several apparent signs of malfunctioning. For you to be able to spot any of these, here is a list of the 5 most common water pump failure symptoms explained:

Coolant leaks

Water pump leaking is one of the most evident and common indications of pump failure, making it a clear sign that it’s time to replace it for a new one. Coolant leaks represent themselves as a puddle of coloured coolant (usually green, orange or red) on the ground, right under the parked vehicle.

This happens because the coolant is stored in the pump using a series of gaskets and seals. Once one of these parts wears out, loosens or cracks, the coolant will eventually leak outside of the engine.

If this is the case, we suggest you to drive your vehicle as soon as possible to your closest workshop, as it can still mean a relatively easy and minor fix.

Whining noises

If you hear a high-pitched whining noise that comes from the front of your vehicle while accelerating, it might be a sign that your water pump is dying. The pump needs pulley belts and bearings to function, and if one of these components remain to loose or are worn out, it will make a sound commonly described as harmonic buzzing. 

In many cases, the belt can be component responsible for this sound. Having it replaced along with your vehicle’s maintenance schedule will keep you safe from more serious damage.

Temperature rises

A dying water pump is unable to circulate coolant through the vehicle’s engine and, as a result, the engine will overheat or run at unstable temperatures. If the engine gets too hot, the chance of serious damage is extremely high. 

Overheating can strongly damage the pistons, cylinders, and the engine’s head gasket, potentially resulting in engine breakdown. So, keep an eye on the temperature gauge and, if there is a considerable rise on temperature, take it immediately for inspection or it might end up not being repairable.

Keep learning: Car temperature: Key aspect in a vehicle’s performance

Surfacing rust and corrosion

Air seeping through a defective pressure cap, non-compatible or dirty engine coolant, mineral build-up, and even age can corrode your vehicle’s water pump. Rust and corrosion on the pump’s surfaces make the pump unable to move the coolant around.

Rust or tiny holes on the water pump’s surface will eventually damage the water pump impellers, the joint between the block and the pump and reduce its efficiency.

When checking the need for a new water pump, pop up your hood and look out for any signs of rust and corrosion on the pump’s exterior. If these show up, it is time to carry out a water pump replacement, as a corroded or damaged one will not properly operate.

Industrias Dolz, your ideal supplier for new water pumps

Premium quality water pumps mean no premature failure or unnecessary leaks. Choosing Dolz as the manufacturer for your water pump will ensure a durable and reliable cooling system solution that will require far less hassles and replacements.

Dolz’s water pumps have their water tightness rigorously checked in a calibrated and extremely precise automatic leak detection machine. This allows us to hold a guarantee rate that is less than a 0.05% in all of our aftermarket car parts.

Dolz has been producing and distributing top-notch water pumps for automobiles and industrial vehicles since 1934. Our nearly 90 years of knowledge and experience prove an optimal replacement option and a wide range of references that comprises: 

• Water pumps for passenger cars
• Water pumps for industrial vehicles
• Auxiliary electric water pumps
• Variable water pumps
• Electric water pumps
• More than 1,300 PN’s.

Contact us to discover more about our products. In addition, browse through our passenger cars and trucks e-Catalogues to find the most suitable option(s) for you!

La entrada New water pump: Does your car need it? se publicó primero en Industrias Dolz.

Dolz products are constantly being researched to ensure that Dolz-GGT continues to meet the market’s requirements. You can be assured that all components are manufactured to the highest standards.

New additions include timing chain kits for BMW, Mercedes, Citroën and Volkswagen, timing belt kits (with and without water pump) and, water pumps for trucks and also for the North American Aftermarket. 

Click and Download this month New To Range!

Download: New to Range February 2024

About DOLZ

Dolz is a global leader in the automotive aftermarket, manufacturing and distributing cooling and drive system products. Our experience as manufacturers allows us, thanks to an entire in-house manufacturing process, to offer to our customers the best possible level of service.

With innovative technologies, Industry 4.0, and in-house production, we have locations in more than 70 countries around the world and three factories in Spain (Castellón), Argentina (Buenos Aires) and China (Shouzou).

All DOLZ/GGT’s new references are in stock and ready to be shipped. For more information regarding our latest products, please contact our customer service on dolz@idolz.com / (+34) 964 340 038 or contact your Dolz Distributor

La entrada New To Range – February 2024 se publicó primero en Industrias Dolz.

La entrada Water pump replacement: all the things you need to know se publicó primero en Industrias Dolz.

In today’s article we explore the effects of pump impeller cavitation, and we also talk about the preventive measures that must be taken against this phenomenon and keep water pump in safe working condition.

The impact pump impeller cavitation

Pump impellers can tolerate a small amount of low energy cavitation without damage or significant reduction in life. The more intense the cavitation is, the quicker the water pump will be damaged.

In other words, cavitation causes pump performance deterioration, mechanical damage and erosion to the impeller as we can see in the following pictures (which can ultimately lead to pump failure).

The impeller is one of the key components of a water pump, essential for its efficiency and performance within the cooling circuit. But what is impeller in pump? The impeller is the rotating component responsible for moving coolant efficiently through the system, ensuring optimal engine temperature and preventing overheating.

Keep reading: The importance of the water pump impeller

There is also the possibility of material release from the blades and even from the volute as well.

Under normal conditions, the impeller of a water pump do not show any deterioration and can only be encrusted with settled solids build-up on their blades.

Are there any signs of failure on the vehicle?

The answer is Yes, but we must address a few explanations first to understand what cavitation is and how it affects the operation of the cooling system.

The first issue to highlight is that any liquid and in general any material can exist in liquid, solid or gaseous state. In this case, the coolant state basically will depend on two parameters: pressure and temperature (during a phase-change process, both are dependent properties).

By decreasing the pressure of the coolant liquid to the same temperature, the liquid will turn into a vapor state. And vice versa, if we increase the pressure of a gas, it will become a solid.

The coolant circulates throughout the engine coolant circuit. This is a closed-loop and sealed system by the radiator cap or the expansion tank cap.

When we start the vehicle’s engine, the heat from the turbocharger and the engine cylinder head heats up the coolant and thus the pressure in the circuit increases. At that moment, two situations can occur:

1. If the pressure of 1.0 bar is exceeded, the circuit pressure is relieved by opening momentarily.
2. If the cap does not close the cooling circuit, the pressure automatically decreases (being atmospheric).

How is cavitation done?

Cavitation in the water pump happens in two phases. Initially, the coolant exposed to high temperatures begins to evaporate and forms the bubbles that constantly burst into the coolant that circulates through the water pump.

The process that initiates cavitation is a sudden pressure drop and/or coolant temperature increase, that is: rapid changes in pressure. This occurs when the coolant liquid passes from the suction side of the impeller, and the pressure decreases, the liquid molecules turn to vapor. But when the impeller increases the speed and transfers the energy of that vapor, this vapor becomes coolant liquid again. Ejecting (in an explosive way) bubbles that collapse, creating an intense shockwave that hits the impeller and creates pump vibration and mechanical damage as we have observed previously.

How to prevent pump cavitation?

By preventing cavitation, you will significantly increase the efficiency and lifespan of your water pump. Among the main causes of cavitation in cooling systems is the incorrect use of coolant.

To avoid it, it is important to maintain the appropriate coolant fluid level, as well as always use the coolant fluid recommended by the car manufacturer. It is also important to inspect the condition of the water pump or thermostat through preventative maintenance.

Related content: Coolant guide. Suitable coolants for the vehicle.

At Dolz we also recommend that, if you see the impeller has material loosening, do not replace just the water pump, replace also the radiator cap or the expansion tank cap in the same operation.

In conclusion, good design to avoid cavitation is always the best option. Dolz water pumps have excellent certified quality, equivalent to the original equipment manufacturers. Our commitment to Quality, Service and Innovation has been amply demonstrated for decades, been recognized as one of the leaders in the manufacture of water pumps in Europe.

If you need any help identifying which components you need for your system or further information about Dolz’s water pumps for passenger cars, heavy duty or commercial vehicles, don’t hesitate to contact us at dolz@idolz.com.

Don’t compromise on quality!

La entrada An overview to pump impeller cavitation se publicó primero en Industrias Dolz.

This popular water pump, suitable for the VAG group, applies to a wide range of applications. More than 14.5 million vehicles are in circulation throughout European roads with this reference.

One of the most popular applications that we find is the Volkswagen Golf D 1.6, 77kW that has been manufactured since 2012 until the present. With engine code CLHA, there are more than 142,000 registered vehicles.

What is the A255V Water Pump Solenoid?

If we look at the water pump, we see that it has an electric switch. But what is this connector? Is it a sensor? What is it for?

Many mechanics have doubts, some of them think that this cable is a temperature sensor, but this is not like this. It is a solenoid, or which is the same, an electromagnetic device that features electromagnetic linear actuation when subjected to an electric current.

To start with the basics, let’s review the vital components of a solenoid, which are a conductive, a coil of wire and ferromagnetic cylinder.

When electric current in the solenoid flows through the coil, a magnetic force is produced, and the plunger moves to the left.

Conversely, if no electricity flows through the coil, the plunger simply stays closed.

How does a solenoid work?

As seen in Figure 1 we see that when no electricity flows through the solenoid, the ball remains intact, keeping the circuit open (blue color) and allowing the coolant liquid through the conduit. On the contrary, in Figure 2 we can see that when electricity passes through the solenoid, the plunger pushes the ball to the left, closing the internal coolant circuit (red color).

Here is a more visual example of both situations:

• NO electricity by the solenoid.

The coolant circuit remains open because the solenoid does not block the circuit, giving the maximum flow depending on the engine speed.

• If current flows through the solenoid.

The magnetic field induces a force that pushes the ball, closes the internal coolant circuit and then generates a pressure and the shield will extend to cover the impeller. Which will result in the blockage in the coolant outlet of the water pump.

All this will make it easier for the engine to reach its optimal operating temperature faster.

What conclusions can we draw?

1.- The solenoid is not a sensor, in simple words, the solenoid is a device that converts electrical energy into mechanical work.

2.- If we connect the solenoid to a mechanical pump (not variable/switchable) it will not give any error in the control unit. If the electronic control unit gives an error from the water pump, it is because the solenoid is damaged, and it will have to be replaced.

3.- When replacing the water pump, if the existing solenoid works properly, we can use it to place it in the new water pump.

How to install solenoid in the water pump?

Wondering how to install a water pump with or without an impeller shield? Some mechanical versions of water pumps lack this shield, leading to questions about connecting the solenoid. Should you connect it or not?

What happens if we connect the solenoid to these pumps? Should we connect it or not?

Mechanically there is no problem. You can connect the solenoid without any issues, this won’t function. The mechanical pump will have the same maximum performance as a switchable design. However, we always recommend connecting the solenoid to the mechanical water pump to ensure the device doesn’t move around the engine and can be damaged.

To correctly install the solenoid, we first proceed to unscrew it and remove it from the old water pump. Then, as recommended by Industrias Dolz, it is screwed into the new one, regardless of whether the version is, variable or mechanical.

For further information on any of our product lines, receive commercial information or technical product specifications (including assembly notes), CLICK HERE.

La entrada DOLZ Answers: FAQ’s about the A255V water pump se publicó primero en Industrias Dolz.

It is considered essential to maintain a good condition of the system and always use suitable coolant liquids. So, to ensure tightness and prevent liquid leaks to the outside, the water pump has a dynamic seal.

The seal is performed by the continuous contact between two highly polished flat sealing surfaces:

1. a hard material (ceramic or silicon carbide – 95% of the pumps manufactured by DOLZ have a dynamic silicon carbide seal) and
2. another self-lubricating surface (natural or synthetic graphite).

Both are held in contact by the controlled pressure of a spring, one of the surfaces turns in unison with the pump’s shaft, and the other is held hermetically attached to the body of the pump.

Water pump replacement

The excellent quality of DOLZ water pumps with the highest reliability and durability (claim rate less than 0.05%) is not enough if special care is not taken with two very important aspects:

1. The old coolant must be drained, and the coolant expansion tank cleaned or replaced if heavily soiled, including the upper radiator until the outflowing water is clear and deposits have been removed.
2. Make sure the air that has entered in the system is removed by bleeding. Always follow the manufacturer’s maintenance recommendations found in your vehicle’s owner’s manual. The presence of air pockets in the circuit, in addition to decrease in cooling capacity, generates overpressure that can exceed the pressure of the spring that regulates the contact of the surfaces of the dynamic seal. Under these conditions, the dynamic seal acts as a safety valve, opening the contact of the surfaces and allowing the escape of liquid until the interior pressure of the circuit has normalized.
3. Remember, only it is necessary the use of sealant paste in those references where the water pump is not supplied with gasket. Some pumps are sealed with O-rings on their inlets and outlets and, in most cases, no sealant is required.

Related content: Why check the antifreeze in summer?

Garage good practices: water pump’s lifespan

Manufacturer recommendations:

• Avoid mixing different types of coolant (mineral, organic and hybrid).
• Never use distilled water in your cooling system, much less tap water, into the expansion tank.
• Recommended monoethylene glycol (MEG) concentration for freezing and boiling point is 50%.

Otherwise, it will start to leak and therefore lose coolant agent. This will result in corroded solid particles or deposits that can clog or be carried away as suspended solids due to agitation caused by the flow of the water pump and, as a result, destroy the mechanical face seals of the water pumps.

Types of residues

• Iron oxide: brown in colour and very obvious to the naked eye, this oxide blocks radiators and wears out pumps. A descaling solution must be used,
• Aluminum oxide: coolant becomes brown or completely black, it blocks the radiators just like iron oxide. A descaling product must be used,
• Oil residues: Oil residues located in the upper part of the expansion vessel or in the radiator cap. Caution: check the condition of the sleeves. A descaling solution must be used.

In the following pictures we can see how affects this correct or incorrect use to the water pump:

1. SUITABLE coolant

The alkaline PH of these coolants and the accumulation of these acids lowers the pH of the engine coolant composition gradually darkening the water pump surfaces that have been in contact with them. This effect is normal and indicates it’s the suitable coolant.

2.  UNSUITABLE coolant: appear of solid residues in the cooling system

Yellowish and reddish colouring, white spots, incrustations, the presence of white or red rust, indicate the use of an unsuitable coolant which will damage the two contact surfaces of the dynamic seal and cause the pump to leak.

The weep hole drains also provide information on the conditions of the coolant used as we can see below:

DOLZ water pumps, tested quality

Now that we know how to replace the water pump to ensure its durability and good performance, let’s see what benefits DOLZ-GGT water pumps offer:

1. 95% of the water pumps are manufactured with a silicon carbide seal.
2. Design according to OE specifications.
3. Optimal leak tightness and longevity of all water pumps through rigorous calibration tests.
4.  2-year warranty from the date of purchase or 50,000 km.

How do we guarantee the water pumps competitiveness and quality?

Dolz offers its customers a tried-and-tested product for an optimum performance.

Different quality controls are defined in all production stages. All of them, are integral to ensuring success – be it in manufacturing or delivery of services. These are: Aluminium pressure die casting / Product operations (shot blasting, stamping, grinding, etc.) / Machining / Assembly / Packaging.

Keep reading: Edless quality. Discover DOLZ Total Quality Control Process.

All this controlled in accordance with the most demanding quality standards, always matching Original Equipment Quality, to ensure that safety, performance, and quality are outstanding.

Furthermore, these quality tests involve every stage of the manufacturing process. This helps to identify where a problem is occurring and the corrective steps you require to prevent it in the future.

La entrada Garage good practices: water pump replacement se publicó primero en Industrias Dolz.