Hoses for your car

Circulating fluids in the car - Hoses

Hoses have an important function in automotive construction. They are the cheaper and flexible version of ducts. Depending on the circulated medium, different hoses are used. All hoses have in common that they are under heavy strain in their own specific way. Therefore in case of a defect, complete replacement is recommended.

Different types of hoses in the car

The following hose types can be found in the car:

• intermediate pressure hose
• air hose
• coolant hose
• hydraulic high-pressure hose
Pressureless hose for air

The simplest hose version can be found in the inlet duct. These components are not under high technical strain and their production is correspondingly cheap. They have the task of conveying the intake air to the engine. A special air duct is installed within the engine: the crankcase ventilation, enabling a pressure adjustment between crankcase and cylinder head. The crankcase ventilation generally consists of a simple rubber hose, which can be easily replaced in case of leakage. Another air duct is found in the brake booster of many cars. It must be kept under a permanent vacuum. Pressure is maintained at only – 1 bar, although the hose should not under any circumstance become deformed. This is why only an original spare part can be installed here. All "makeshift" solutions with unsuitable hoses unavoidably lead to a deterioration of the braking performance.

Low pressure at high temperatures: hoses for the cooling system

The largest and longest hoses are found in and around the cooling system. The hoses are installed in the following places:

• from the expansion tank to the engine as well as to the radiator.
• from the radiator to the engine.
• from the engine to the engine (small cooling circuit).
• from the engine to the heat exchanger (interior heating).

Pressure in water hoses does not exceed 1 – 2 bar. Nevertheless they must be able to withstand antifreeze agent and high engine temperatures. Therefore only the right antifreeze agent should be used. The wrong antifreeze agent can affect the hoses and cylinder head gasket on the inside. Coolant hoses are generally easy to replace. They are fixed with simple clamps which can be removed with a screwdriver or pliers. If oil is found in the coolant, the hoses should be replaced immediately after removing the cause. Oil also has a deteriorating effect on the rubber.

Intermediate pressure hoses for fuels

Diesel, petrol and more recently DEF are conveyed from the tank to the combustion chamber under amazingly high pressure. Depending on the type of vehicle, 5 bar or more is applied. The pressure lines generally consist of rubber, reinforced with glass-fibre. Furthermore, these hoses must be able to withstand corrosive fluids. Diesel, fuel and particularly DEF affect many materials. Here also applies: always the right hose at the right point. Otherwise you run the risk of clogged or ruptured hoses with fatal consequences.

High-pressure hoses for brakes and power steering

Hydraulic pressure is a fascinating technical principle, generating high power with minimum effort. This is only possible if the corresponding high pressure is previously built up in the hydraulic system. Pressure hoses for power steering therefore must be able to withstand up to 200 bar, which makes these components high-grade and accordingly expensive. The use of second-hand power-steering hoses is nevertheless advised against. You never know how often the previous owner has changed hydraulic oil. The risk of purchasing a damaged hose is too high. Brake lines consist mainly of copper lines. Where the brake oil is conveyed from the fixed lines to the rotating wheel, a flexible pressure hose is indispensable. Generally, glass-fibre reinforced rubber hoses are installed here. Many car owners now opt for replacement of these simple and cheap hoses by stainless steel flex hoses, enabling a maintenance-free and durably reliable situation.