Smart Fluid Systems


Customized products

COHLINE has represented expertise and innovation since 1932. We manufacture pipe and hose line systems for various applications including oil supply, turbochargers, fuel, cooling and hydraulics. Explore our tailored solutions to meet your specific requirements.

Our products adhere to the highest quality standards of renowned companies in the international automotive, commercial vehicle, construction, agricultural machinery and engine industries. Our primary focus in every development project is on the individual requirements of our customers. Regardless of yout needs, we are able to develop and provide sophisticated customer solutions utilizing cutting-edge production technology. At COHLINE, we continually strive to devise well-conceived, practical and strictly customer-oriented system solutions. Our highly qualified research and development team actively contributes to setting standards and specifications while consistently experimenting with new, innovative manufacturing processes.

Our proficiency in working with metals such as steel, stainless steel, aluminum, brass and copper, plastics such as polyamides and PTFE and elastomers such as NBR, CR, EPDM, CSM, FPM, AEM and ECO enables us to combine these materials and achieve the best possible results. Our focus is on function, quality and maximum precision - combined with an optimum price-performance ratio.

Fuel Lines

For over 40 years, COHLINE has been supplying fuel system lines to renowned automotive manufacturers. Fuel lines transport fuel from the tank to the engine. They are typically made of metal or plastic and may have different diameters and connections depending on the vehicle type.


  • Conventionally powered motor vehicles
  • Commercial vehicles
  • Hybrid vehicles
  • Agricultural and construction machinery
  • Marine engines
  • Emergency power generators

Different types of lines:

  • Low-pressure fuel lines: Pressure range up to 8 bar operating pressure
  • High-pressure fuel lines: Pressure range up to 350 bar operating pressure
  • Ventilation/regeneration lines: Pressure range up to 5 bar
  • Fuel lines with integrated sensors: Pressure or temperature sensors

Permeation-optimized hose assembly:

4-layer hose FPM/ECO/pressure carrier/ECO

Leakage rate of the line <1.0x10-4 mbarl/s, Test medium: 100% helium, Test pressure: 3.8 bar

Various connection fittings:

  • Pipe hose nipples in different materials
  • Rotary fittings
  • Plastic fittings
  • Various connectors

Specialized tailored press sleeves for hose assembly:

  • Single and multiple-row crimping
  • Spring band clamps
  • Click clamps
  • Single ear clamps

Various designs and materials:

  • Pipe/hose lines: inlet and return lines as connection between engine and body in various material combinations
  • Steel/stainless steel: engine-side fuel lines
  • Polyamide pipe with hose or metal pipe: regeneration lines, activated carbon filter (AKF) lines
  • Polyamide pipe with hose or metal pipe: body-fixed lines between tank and engine compartment

Turbocharger Supply

Turbocharger supply lines are special lines that ensure the smooth operation of turbochargers in combustion engines. Turbochargers increase the performance of an engine by feeding additional air into the combustion chambers. This additional air enables more efficient combustion and increases the engine's power output. Here are some types of lines used in the turbocharger supply:

  • Charge air duct: The charge air duct transports the compressed air from the turbocharger to the engine's intake ports. It is usually made of metal pipes or hoses that can withstand the high pressures and temperatures that occur in the charge air system.
  • Compressed air line: This line transports the compressed air from the air intake system or from a separate air compressor to the turbocharger. It ensures that the turbocharger is properly supplied with sufficient air flow for compression.
  • Oil supply line: Turbochargers require lubricating oil in order to work smoothly and cool down. The oil supply line transports the engine oil from the engine's oil circuit to the turbocharger to ensure sufficient lubrication and cooling.
  • Oil drain line: This line allows the cooled and used engine oil to flow back from the turbocharger to the engine oil circuit. It ensures that the oil drains properly and that the lubrication of the turbocharger is maintained.
  • Cooling water line: A turbocharger system can include a water cooling system, which is supplied with appropriate cooling water lines.

Different types and materials:

  • Elastomer hoses
  • PTFE hoses with stainless steel braiding
  • Stainless steel tube
  • Stainless steel bellows tube
  • Stainless steel corrugated hose

In addition, the components can be protected from heat radiation by applying protection to the outside of the cable.

Various protection options:

  • Heat protection hoses
  • Heat protection mats
  • Heat protection plates

Engine Cooler Lines

Motor oil cooler lines are special pipelines that connect the oil cooler of a vehicle to the engine oil circuit. They serve to cool the engine oil in order to maintain an optimal operating temperature and prevent engine overheating. They are typically made of metal pipes or flexible hoses that are heat-resistant and oil-resistant. They are designed to withstand the high pressures and temperatures that can occur in the engine oil circuit.

There are different types of motor oil cooler lines, depending on the vehicle configuration and the design of the oil cooler system. The most common types include:

  • Forward lines carry the hot engine oil from the engine to the oil cooler. They are usually connected to the oil filter or the engine's oil circuit and transport the oil to the oil cooler, where it is cooled.
  • Return lines carry the cooled engine oil from the oil cooler back to the engine. The cooled oil is directed back into the engine's oil circuit through these lines to continue the lubrication process.

Various types and materials include:

  • Steel
  • Stainless steel
  • Aluminum (bare, PA-coated)
  • Polyamide pipe PA 6.10, PA 6.12
  • Elastomers such as AEM can be executed with an appropriate pressure carrier braid according to requirements.

Tolerance and movement compensation are ensured either by a hose portion or the geometry of the line in plastic lines. The sealing of the interfaces to the engine and cooler is done via an O-ring, which can sit on a turned part, a compression or in a connector. In plastic lines, the connection components (gear connection, connector) are either pushed in or welded on.

Transmission Oil Lines

Transmission oil cooler lines are pipelines used in vehicles with automatic transmissions or in other machinery with transmission systems. They serve to transport transmission oil from the transmission to a cooler, regulating the operating temperature of the transmission oil and protecting it from overheating. Transmission oil cooler lines are designed to withstand the high pressures and temperatures that occur in the transmission system. They are equipped with hoses, pipes, and fittings to guide the transmission oil through the cooling system and dissipate heat.

The cooler supplied by the transmission oil cooler lines can either be a separate cooler or integrated into the vehicle's radiator. The cooling medium flowing through the cooler can be air or coolant, such as engine coolant.

Various types and materials include:

  • Steel
  • Stainless steel
  • Aluminum
  • Plastics
  • Elastomers such as AEM can be executed with an appropriate pressure carrier braid according to requirements.

Tolerance and movement compensation are ensured either by a hose portion or the geometry of the line in plastic lines. The sealing of the interfaces to the transmission and cooler is done via an O-ring, which can also sit in a connector.

Oil Dipstick Guide Tubes

Oil dipstick guide tubes, also known as oil dipstick guides or oil dipstick tubes, are components in internal combustion engines that accommodate the oil dipstick and guide it into the oil sump. They serve to monitor the oil level in the engine and ensure an adequate supply of lubricating oil.

The oil dipstick guide tube is typically made of metal or plastic and is usually located near the oil filler neck or the oil pump. It has a specific length and shape that allows for the insertion of the oil dipstick and reading of the oil level.

To check the oil level, the oil dipstick is inserted into the oil dipstick guide tube until it reaches the bottom of the oil sump. Then, the dipstick is pulled out, and the oil level is read based on the markings on the dipstick. This provides the vehicle owner or mechanic with an indication of whether the engine is adequately supplied with lubricating oil or if oil needs to be added.

Various types and materials include:

  • Aluminum
  • Steel
  • PA (polyamide)
  • With mounted oil dipstick (optional)

Various attachment options:

  • Holders soldered on, e.g., aluminum or steel
  • Holders molded on, e.g., plastic

Sensor Lines

Media-carrying lines with integrated sensors are special lines that not only serve for the transportation of liquids, gases, or other media but also feature integrated sensors to capture and monitor various parameters of the medium. This type of lines is often employed in industrial applications where continuous monitoring and control of the medium are necessary. Sensor lines can be found in various systems of the vehicle.

Various types of implementations include:

  • Integration into a fuel system
  • Integration into a cooling or heating system
  • Integration into a brake or steering system

Different types of sensors and measurement capabilities include:

  • Lines with pressure sensors: Pressure sensors measure the pressure of the medium in the line. This signal can be used by a system for monitoring and controlling the pressure.
  • Lines with temperature sensors: Temperature sensors measure the temperature of the medium in the line and can be used to monitor the condition of the medium or the efficiency of a heat exchanger.
  • Lines with flow rate sensors: Flow rate sensors or flow sensors measure the flow of the medium in the line and can be used to accurately determine the consumption of the medium or to trigger alarms if the flow is outside the expected range.
  • Lines with level sensors: Level sensors measure the level of the medium in the line and can be used to accurately determine consumption or to trigger alarms if the level is too low or too high.
  • Lines with leakage sensors: Leakage sensors can be installed to detect leaks or breaks in the line and to prevent damage or contamination.

For the manufacturing of sensor lines, we utilize our corresponding ESD workstations.

Cooler Lines

Power steering systems

Power steering systems are hydraulic assists for vehicle steering. These systems consist of various components, including a suction line that transports servo oil from the reservoir to the pump, an expansion hose that leads the oil from the pump to the steering gear, and two return lines that direct the oil from the steering gear through the oil cooler back to the oil reservoir. In most cases, the suction line consists of a robust hose, especially if the oil reservoir is located near the pump in the engine compartment.

When longer distances need to be bridged between the oil reservoir and the pump, pipe/hose combinations are used. An expansion hose typically consists of several hose sections with various fittings to dampen vibrations caused by the pump and prevent their transmission to the vehicle body. Resonators and throttles are used in combination with the volume expansion of the hose to achieve a vehicle-specific acoustical tuning.

Different types of lines include:

  • Expansion hose lines: Pressure range up to 120 bar operating pressure
  • Return lines, suction lines
  • High-pressure lines: Pressure range up to 180 bar operating pressure
  • Power steering oil coolers: Smooth tube, CSC tube (crimped), ribbed tube (various rib heights possible)

The return lines typically consist of pipe and hose sections that are connected to the oil cooler via connectors. Connectors are used because the cooler is preassembled on the front end of the vehicle, while all other lines are at the engine. During the vehicle's assembly process, the power steering system can be closed with the cooler using the two connectors.

Power Steering Oil Coolers - Smooth Tube, CSC Tube, and Ribbed Tube

For such systems, a tube is used as the oil cooler, which can be designed with different cooling levels. It can be a smooth aluminum tube placed directly in front of or beneath the main cooling package in the vehicle's front end to utilize the airflow while driving. Improved cooling performance can be achieved by adding indentations to the tube, increasing the surface area of the "cooler," resulting in higher heat dissipation. Turbulences are created in the volume flow of the power steering oil in the cooler, leading to better heat transfer of the medium to the tube wall.

Another option to enhance performance is to use ribbed tubes. These tubes are made of thick-walled aluminum tubes into which ribs of varying heights can be rolled, depending on the desired cooling performance. The inner geometry of these lines can also be designed to induce turbulence in the medium, enabling more efficient heat transfer.

Water Lines

No matter what the challenge is - high media temperature, radiant heat, or media resistance - COHLINE always has the right solution for you with its portfolio of materials and heat protection agents. We are happy to design the lines to fit your installation space.

For cooling electronic components

As electromobility advances, the cooling of electronic components becomes increasingly important. COHLINE provides suitable and cost-effective solutions for battery or control unit cooling, for example.

For cooling internal combustion engines

Compact installation spaces and high power density result in high temperatures in components such as engines and turbochargers. Efficiently dissipating this heat is the task of the cooling water. Coolant-water mixtures in vehicles serve to dissipate heat from heat sources and supply other areas such as interior heating. Excess heat is directed to the vehicle radiator located in the front end and is passed through by the driving wind, cooling the coolant, which is then returned to the engine system.

The transport of coolant between the individual components and parts is carried out through lines that, depending on the application requirements, can consist of various material mixtures.

Various types and materials:

  • Pipe sections are typically made of aluminum.
  • Stainless steel pipe is used for hotter applications.
  • Plastic pipe is used for lower temperatures.

Tolerance and movement compensation between components are ensured either by hose sections or by the geometry of the components. We also use different materials for hoses depending on the application's pressure and temperature requirements (EPDM, VMQ, PTFE).

Additionally, the components can be protected from heat radiation by applying a protective layer on the outside of the line.

Various protection options:

  • Heat protection sleeves
  • Heat protection mats
  • Heat protection plates

Hydrogen Lines

Hydrogen lines transport hydrogen gas from one location to another. They must meet specific requirements because hydrogen is a highly reactive gas. There are various types of hydrogen pipelines, depending on the pressure and temperature conditions as well as specific applications.


Hydrogen for high-pressure applications up to 700 bar or greater Hydrogen for low-pressure applications up to 25 bar For fuel cells, for tank systems, for internal combustion engines.

Various types and materials:

Stainless steel piping for high-pressure applications Plastic piping for low-pressure applications Pipe-hose combination for low-pressure applications.

Various connection fittings:

  • Ball head
  • Conical seal (low pressure)
  • O-ring (low pressure)
  • VOSS-Lok 40
  • Swagelok

Brake Lines

Hydraulic Brake Hose Lines

From the world's largest manufacturers to your local workshop, COHLINE hydraulic brake lines are manufactured to the highest safety standards. Developed with an inner and outer layer of EPDM with dual-layered PET reinforcements and an intermediate layer of SBR+NBR, they are resistant to DOT 3 and DOT 4 and most non-petroleum-based brake fluids. They comply with the specifications of SAE Standard J 1401, FMV SS 106, GB 16897, and DIN ISO 3996. COHLINE's extensive range of hydraulic fittings can be used in all standard vehicles. The fittings are Cr6-free zinc-plated, silver-transparent passivated, and compliant with EU recommendations 2000/53/EC and 2002/95/EC.

COHLINE manufactures hydraulic brake hoses according to customer-specific requirements.

Hydraulic brake hoses must meet high quality and testing standards and are therefore not suitable for self-assembly by end customers. However, we offer the option to purchase COHLINE equipment and provide training on the handling of self-assembly. For further information, please feel free to contact our sales department.

Brake Lines

COHLINE brake lines - the safety lines of vehicles.

For original COHLINE brake lines, the highest quality standards for materials and workmanship are a must. COHLINE is certified according to IATF 16949, ISO 14001, and ISO 45001. Our promise to our customers: We develop and manufacture our products according to an internationally recognized quality and environmental management system.

COHLINE brake pipes Type 1035 are double-walled rolled pipes made from a single flat strip, coated internally and externally with copper. Additionally, the pipes are provided with an outer zinc coating and coated with a PVF plastic. In the salt spray test according to SS DIN 50021, the corrosion protection is 3,300 hours.

The quality of COHLINE brake lines is characterized by pressure stability and precision, meeting the requirements of DIN 74234. The installation of a brake line must be stress-free. The brake lines are manufactured according to the high quality standards of the German automotive industry.

For our brake pipe lines, we offer matching, zinc-plated Cr6-free fittings, which are silver-transparent passivated and compliant with EU Recommendation 2000/53/EG and 2002/95/EG.

We would be happy to send you corresponding catalogs and price lists upon request.

Clothes Hanger

The COHLINE Clothes Hanger: elegant, durable, and high-quality

Manufactured from stainless steel tubing for the automotive industry, the high-quality clothes hanger offers an optimal combination of strength, weight, and design.

Here's what sets our clothes hanger apart:

  • Matte, non-staining surface
  • Rust-resistant
  • Shape retention up to 6 kg, excellent for jackets and uniforms

Whether in the home, office, cafeteria, bar, restaurant, or hotel, the COHLINE Clothes Hanger makes a high-quality impression anywhere.

Order via Amazon:

You can purchase our clothes hanger directly on Amazon: Stainless Steel Clothes Hanger in a pack of 5