The engine cooling system is designed to stabilize operating temperature, limiting its increase within precise limits. The water pump circulates the coolant and ensures its correct flow at any given engine rpm. Maximum accuracy is a prerequisite. Each component of the water pump is studied, designed and manufactured according to strict specifications. The pump housing geometry is based on technical considerations such as housing stress, but also the morphology of the entire cooling circuit. This means that we have the specific vehicle in mind when we’re developing the pump. Every Metelli Group water pump is tested during its assembly with a careful check of the pressfit load dimensions value. This is followed by specific tests for impellers and bearings on the test benches, assembled pump tightness test and pulley and impeller materials hardness test. Test results show that our water pump performance exceeds that of the main premium competitors, both in terms of durability and temperature management. Through our specialised work in this field we have developed and patented new water pumps. And we have a range of nearly 1000 items available for Passenger cars, LCVs and Trucks.


During the design phase we analyse the body structure of the original sample trying to improve possible weak points. (FEM analysis) From our foundry we obtain excellent aluminium (90% of our range) and iron casts, which make it possible to bear the engine vibrations, loads and high temperatures the water pump is subjected to. For this reason, we rely on the best suppliers in the sector because we believe that it is fundamental to start from a solid basis to develop excellent water pumps. Differently from some of our competitors and, in some cases, from the same original product, we decided to machine the surface that interfaces with the engine crankcase to reduce the risk of leaks, preventing thus complaints from the final user or returns from the market.


The water pump is a very important component because not only must it ensure the circulation of the coolant but it must also absorb part of the loads from the distribution belt group or Poly-V. Latest-generation engines have increasingly higher power with very high tension loads on the distribution units. To withstand these loads and the engines' high revolutions, we use the best integral bearings which, depending on the specific applications, can be ball-ball, roll-ball or outer radial.


On our pumps we use mechanical seals with state-of-the-art materials, such as silicon carbide: the most prestigious materials for mechanical seals providing good resistance to wear and tear also in particularly challenging conditions, high thermal conductivity compared to other ceramic materials, good resistance to thermal shock and good chemical inertia.


All pulley are made with phosphate sheet, cast iron or sinterised steel so that they can withstand the continuous loads and vibrations produced by the drive shaft or auxiliary systems, reducing thus the generated noise. Each pulley is dynamically balanced with high precision instruments.


Thanks to our engineers know-how and to the variety of materials, one of the strong points of our water pumps are the impellers. They are made using different materials (metal sheet, brass, plastic, stainless steel, cast iron) and with various geometries and they guarantee capacity performance and prevalence similar or higher than the original parts.


The 70% of our pumps are provided with nitrile seals (HNBR) that are very resistant to chemical and corrosive substances. The 28% of our seals are paper or metal/rubber. The remaining 2% uses the sealing paste according to the provisions of OEM. Our seals guarantee the best tightness between the pump surface and the engine crankcase, ensuring thus excellent tightness at high temperatures.