Know the different versions of our water pump


Currently on the market you can find different types of water pumps such as mechanical water pumps, variable water pumps, electric water pumps…

Mechanical water pumps had relied solely on engine motion. However, the current trend of refrigeration on demand has come to evolve this type of pump, offering variable versions and technological advantages that allow more efficient operation.

This article reflects an overview of the different versions that Industrias Dolz offers of its water pump OE 04L121011 and shows in detail their differences in terms of design and functionality.



Water pump versions OE 04L121011


Dolz offers three versions of the A255 water pump on the market. On the one hand, we find its two mechanical options: A255 and A255E, the latter being an ‘economy’ version as it has an IAM design in its internal bearing. 

On the other hand, there is the third and most innovative version, the variable water pump A255V and which we will later discover its particularities in design and behavior.

OE 04L121011 is suitable for more than 350 applications, also from Audi, Seat, Skoda and Volkswagen models with TDI diesel engines manufactured since 2009, including vans such as the Volkswagen Caddy, Multivan, California or Transporter, up to applications for the most modern models such as Volkswagen T-Roc, Golf 7, Seat Arona or Ateca, Skoda Kodiaq or Karoq, Audi A3, A4, etc.


 A255, A255E


Mechanical version: A255 y A255E


Mechanical water pumps are the most common on the market.

The importance of the water pump has generated the continuous search for alternative technologies to be more and more efficient. Therefore, given the evolution of this component of the cooling system, there are increasingly more complex water pumps on the aftermarket that have more electronics and more complex designs. 

Although it is true that all of them, regardless of their version, are designed to fulfill the same function: Internal combustion engine cooling.

A255 and A255E mechanical water pumps have a turbine that, with the help of the motion of the crankshaft, projects the coolant towards the engine block. They are connected to a pulley by a bearing shaft that is driven through the timing.


Variable version: A255V


Unlike mechanical pumps, a variable water pump supplies coolant based on the needs of the engine.

A255V water pump therefore allows a more precise control of the flow throughout the cooling circuit. And this is due to its electric actuator based on the on/off principle that adapts the capacity to the different motor operating conditions.



Differences about Design


In terms of design, there are two main differences. Let’s see the picture below:


different water pumps


A255V, unlike the mechanical version, it has a ring around the impeller, which receives the order from the vehicle’s control unit to go up or down, allowing the impeller to run or not the coolant.

Depending on the point of operation, the actuator pushes the adjustable ring in or releases it again.

On the other hand, there is a difference in the water pump bearing. While A255 and A255V have an external bearing, the ‘economy’ version has a different design incorporating an internal bearing. 



Read more:Discovering the main water pump components



Assembly instructions

water pump assembly


For A255 and A255E (mechanical version) please unscrew the electric switch of the original water pump (OE) and screw it into the specific housing as shown in the images.



Dolz, water pumps with the latest technology


DOLZ produces and distributes water pumps for passenger cars and industrial vehicles for the aftermarket since 1934.

Dolz water pumps are ISO 9001:20015 certificate, which means quality 100% tested.

Regarding the quality control phases, the tightness test using a calibrated leak instrument to verify the air pressure drop is within the defined tolerances and thus prevent cavitation.

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.

Among our extensive range of water pumps, you will find:

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

We manufacture more than 5.5 million units per year over a range which comprises more than 1,300 PN’s.

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

…All in Dolz!