Cooling system

Play it safe with engine cooling.

The demands for engine cooling systems are constantly increasing. Today more than ever, new solutions aim to have a positive impact on fuel consumption, emissions, driving comfort and driving safety via heat transfer.
Products from Behr Hella Service are distinguished by their quality, reliability and long service life. The OE know-how and the expertise at Behr are crucial and directly influence our product development.

  • Learn more about the topic of engine cooling with the labeled cooling circuit!

Coolant radiator

The radiator
The most important component of an engine cooling module is the coolant radiator. It consists of a radiator core and water tank with all the necessary connection and attachment elements. The radiator core itself is made up of the radiator network—a tube/fin system—the tube headers and the core covers. Conventional coolant radiators have a coolant tank made of glass-fiber reinforced polyamide that is sealed before being joined and crimped to the tube header. The state-of-the-art all-aluminum radiator is extremely light and compact and 100% recyclable.

How it works
The heat generated by combustion in the engine is absorbed by the coolant and discharged to the outside air via the radiator. Coolant radiators are installed in the air flow at the vehicle front, with different designs available. In the case of downflow radiators, the coolant enters the radiator at the top and emerges at the bottom. In the case of crossflow radiators, the coolant enters at one side and emerges at the other. Crossflow radiators are more compact and are used most frequently in passenger cars. Defects frequently occur due to accidents or leaks.

  • Engine cooling radiators

Expansion tank

The expansion tank is used to trap the expanding coolant from the coolant circuit. High coolant temperature results in the pressure in the cooling system rising as the coolant expands. The increase in pressure is dissipated by valves integrated into the cap of the expansion tank. If the pressure increases, the system pressure is reduced by the valve and brought back to the preset value. When the coolant temperature returns to normal, a partial vacuum forms in the cooling system. This in turn results in the vacuum compensation valve in the tank's filler cap opening. Ambient air flows into the tank until the preset system pressure is reached again.

  • This well-conceived expansion tank from Behr Hella Service receives the expanding coolant

Visco® fans

Dissipating the heat in commercial-vehicle and high-power passenger car engines requires not only high-capacity radiators, but fans and fan drives capable of providing an efficient supply of cooling air as well. Visco® fans consist of a fan wheel and a Visco® fan drive. They are used in the case of longitudinally mounted engines. They are fitted in front of the radiator (direction of travel) and are driven by a V-belt or directly by the engine. A bimetallic or an electronic component controls the fan, depending on the ambient temperature. Controlling the cooling air flows as needed reduces fuel consumption and causes less impact on the environment, including minimizing noise levels and maximizing efficiency.

Additional information about Visco® fans from Behr Hella Service:

  • Using this innovative Visco® fan from Behr Hella Service, save fuel and the environment

Visco® fan drive

The Visco® fan drive is designed to form a frictional connection to the fan wheel and to influence its speed, dependent on the temperature. If no cooling air is required, the Visco® fan drive shuts down and rotates at a lower speed. The Visco® fan drive is actuated by a bimetallic element which is exposed to the ambient temperature. A pressure pin clears a bore hole, which allows silicone oil to flow from the storage chamber to the working chamber. In this chamber, wear-free fluid friction is used to transfer the drive torque to the fan wheel, whose speed is adjusted infinitely in line with the operating conditions. The electrically controlled Visco® fan drive is controlled directly via sensors. A regulator processes the values and a pulsed control current transfers these to the integrated electromagnet. The defined guided magnetic field regulates the valve which controls the internal oil flow via an armature. An additional sensor for fan speed completes the closed-loop control circuit. This increases the dynamics of fan engagement/disengagement. Cooling on demand improves the coolant temperature level, engine noise level and fuel consumption.

Additional information about Visco® fan drives from Behr Hella Service:

  • Using this Visco® fan drive from Behr Hella Service, you can achieve the engine cooling you need

Condenser/radiator fan

A condenser or radiator fan consists of an electric motor with a flange-mounted fan wheel. They are mounted in front of or behind the condenser or radiator. They remove heat from the refrigerant or coolant via the generated air flow. An additional or more powerful fan is usually used in vehicles with an air-conditioning system.
Due to the specific installation point, soiling or rock impacts, for example, can cause environment-related malfunctions or defects. Damage due to head-on collisions is also especially common.

Additional information about condensers and radiator fans from Behr Hella Service:

  • The high-performance Behr Hella Service fan contributes to optimal engine cooling


Improved performance throughout the speed range, lower fuel consumption, optimized engine efficiency, lower emission values, reduced thermal load on the engine—there are a variety of reasons to cool the combustion air of supercharged engines with intercoolers. Basically, two types of cooling can be distinguished. Direct intercooling, where an intercooler is installed in the front end of the car and cooled by the ambient air (wind), and indirect charge-air cooling, where coolant flows through the intercooler, absorbs heat and transmits it to the ambient air.

The numbers of vehicles equipped with turbochargers is increasing all the time. Since almost all modern vehicles with turbochargers are also equipped with intercoolers, this also affects the spare parts market (such as accident repair or impacts from stones).

Notice: Turbocharger damage can affect the intercooler

Mechanical turbocharger damage - Why replacing the intercooler is important!

  • Using this intercooler from Behr Hella Service, you can increase the performance of your vehicle in the entire speed range

Oil cooler/transmission oil cooler

Using oil coolers to cool engine oils that are under a high thermal load, i.e. ensuring a near constant temperature spectrum, has significant advantages. Particular benefits include longer oil change intervals and improved engine longevity.

A differentiation is made as a basic rule between air and coolant-cooled types. Depending on the requirements, the latter can be mounted in the coolant tank or engine block, or externally on the engine, transmission, cooling module or oil filter housing.

Behr’s latest model is a compact and powerful staked plate oil cooler. Since it manages without a coolant housing and is made entirely of aluminum, its outstanding features are its low weight and small package size. Thanks to its modular design its performance range can be modified by changing the number of plates.

  • Benefit from the advantages of cooling the engine oil using the Behr Hella Service oil cooler

Oil coolers for hydrodynamic retarders

Hydrodynamic retarders are used in commercial vehicles as almost wear free hydrodynamic brakes to support the actual braking system. Here, the movement energy of the crankshaft is transferred into the thermal energy of the hydraulic oil which leads to a reduction in the vehicle speed. The heated hydraulic oil then flows through an oil cooler. This part of the retarder feeds the thermal energy via a coolant to the vehicle's main cooling circuit. As a system-relevant part, the oil cooler is flange-mounted to the retarder directly and must withstand extreme temperature and pressure loads. A fault in the cooling system inside the retarder will cause the hydrodynamic brake to overheat very quickly and fail.

Additional information about oil coolers for hydrodynamic retarders from Behr Hella Service:

  • This oil cooler for Behr Hella Service hydrodynamic retarders can withstand extreme loads

Cabin heat exchangers

The cabin heat exchanger is located in the vehicle cabin beneath the dashboard. The air flow produced by the cabin fan is routed through the cabin heat exchanger, which has coolant flowing through it. The heated air is then discharged into the vehicle cabin. Limescale deposits or leaks can render the cabin heat exchanger defective.

  • Using this Behr Hella Service cabin heat exchanger, it remains comfortably warm in your vehicle

Auxiliary heater (PTC)

On account of the high efficiency of modern, direct injection engines (e.g. TDI), dissipated heat is no longer sufficient for heating up the inside of the vehicle quickly on cold days. Efficient units have been developed specifically for these cases. PTC auxiliary heaters, which are installed in the direction of travel in front of the heat exchanger, make it possible to heat up the vehicle cabin more quickly. They are made up of several temperature-dependent, electrically controlled resistors. Without delay, energy is taken from the vehicle electric system and directly transferred to the passenger compartment as heat via the blower air flow.

  • Using this Behr Hella Service PTC auxiliary heater, your vehicle cabin becomes heated faster

Coolers for exhaust gas recirculation

The effect of exhaust gas recirculation is mainly due to the fact that the exhaust gas has a greater heat capacity and lower oxygen content than air. This reduces the combustion temperatures in the cylinder. Temperatures are reduced even more by cooling the exhaust gas and the charge air. Since the formation of NOx depends exponentially on these temperatures, a combination of cooled exhaust gas recirculation and charge air cooling makes it possible to meet the limits of the Euro-5 standard.
Efficient charge air and exhaust gas cooling has a positive effect on both the formation of NOx in the combustion chamber and fuel consumption.

Additional information about radiators for exhaust gas recirculation from Behr Hella Service:

  • This efficient radiator for exhaust gas recirculation from Behr Hella Service has a positive effect on the formation of NOx in the combustion chamber

Water pumps

As central parts of the cooling circuit, water pumps are among the most widely demanded spare parts. They are powered mechanically, transport the coolant through the circuit and build up the system pressure. There have been technical innovations in water pumps, but most passenger cars and commercial vehicles on the market still have belt-driven water pumps. The next generation will be electronically controlled water pumps. These are driven according to requirements, like the compressor in the air-conditioning circuit. This optimizes the operating temperature.

Technical requirements placed on water pumps:

  • Extremely large bandwidth between cold start and operating temperature: max. - 40 °C in winter to around + 120 °C.
  • Pressure differentials of 0.5 bar negative pressure to 3 bar overpressure
  • Pump speeds of approx. 1,000 rpm to approx. 8,000 rpm.
  • Coolant flow rate at 60,000 km: approx. 7.7 million liters (more than 48,000 bathtubs).


The service life of a water pump is heavily influenced by the following factors:

  • Proper installation.
  • Care and maintenance of the cooling system.
  • Coolant quality.
  • Condition and functional capability of adjoining units.


Lack of maintenance, improper use of coolants, corrosion and similar factors can irreversibly damage the water pump. A malfunctioning water pump can be recognized by noises, leaks and engine overheating.

Water pumps and kits from Behr Hella Service fulfill the most stringent requirements. Our thermal management expertise sets true standards for functionality and fit.

Additional information about water pumps from Behr Hella Service:

  • Water pumps from Behr Hella Service fulfill the most stringent requirements, and original equipment quality is the standard for the entire product range!

Water-pump kit

All drive-relevant parts of water pumps are perfectly matched to each other. The parts should therefore be replaced as a set if they have to be replaced during repairs or when the belt comes to the end of its service interval. Behr Hella Service offers complete kits including water pump (including O-rings or other seals), toothed belts, and, if needed, tension, deflection and guide rollers, seals and dampers.

The benefits of more than 150 service-friendly water pump kits:

  • Garages receive all the necessary spare parts to perform complete repair from a single source.
  • Perfectly matched components with proven Behr Hella Service quality.
  • No need to search for suitable spare parts.
  • Errors and incorrect purchase orders are avoided.
  • Number of replacements is minimized.
  • Increased customer satisfaction by saving time for wholesale and garage.

Behr Hella Service also offers more than 600 water pumps in proven Behr Hella Service quality as stand-alone spare parts.

Additional information about water pump kits from Behr Hella Service:

  • Water pump kits from Behr Hella Service fulfill highest requirements, and original equipment quality is the standard for the entire product range!
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