Audi A4, S4

since 2000 of release

Repair and car operation

Check of a condition and replacement of hoses of an impellent compartment, localization of leaks

Replacement of hoses of central air of air should be made at car repair shop of representation office or in a specialized workshop where there is an equipment for safe dumping of pressure in system. Never disconnect hoses of system and do not remove its components, previously without having dumped pressure.

General information

Influence of high temperatures in an impellent compartment leads to gradual failure of the rubber and plastic hoses used in various systems. It is necessary to make regularly check of hoses on existence of cracks, weakening of fastening of collars, hardening of materials and signs of leaks.

Information relating to hoses of system of cooling, is provided below, and to hoses of brake system - in the Section of Check of brake system. Adjustment of the parking brake.

The majority of hoses (but not all) fasten by means of collars. Where collars are used, check reliability of their fastening providing absence of leaks. If collars are not used, make sure that the hose in a junction with the union was not inflated and/or did not harden, allowing leaks.

If there are signs that there is a leakage of any liquid, but you cannot distinguish type of liquid or an exact origin, it is necessary to leave the car for long time and to put a big piece of paper or a rag under the car. It will help to find a place of course of liquid, and also will help to identify liquid on color. But keep in mind that some leaks can be shown only at the working engine.

Vacuum hoses

Usually vacuum hoses which are especially applied in systems of decrease in toxicity of fulfilled gases, differ color or have color strips.

Various systems demand use of hoses with various thickness of walls, thermal stability and various resistance to a skhlopyvaniye. At replacement of hoses watch that the material of a new hose corresponded to a material of the old.

Often only authentic way of check of a condition of a hose is its complete removal from the car. At removal more than one hose take care of accurate designation of hoses and unions to provide the correct assembly.

At check of vacuum hoses do not forget to check T-shaped connections also. Examine them on existence of cracks which can cause leaks.

Using a similar stethoscope, be careful, do not allow contact to moving components in an impellent compartment, such as a driving belt, the cooling fan, etc.)

Leak in a vacuum hose means that air is sucked in in a hose (instead of leaves a hose), and it does leak very difficult for detection. For identification of leakages of vacuum it is possible to use a small piece of a vacuum hose as a stethoscope. When the end of a hose will directly be over the leak place, the hissing sound will be clearly audible through a hose. Hear to all vacuum hoses and connections on existence of the characteristic hissing testifying to leak. It is necessary to avoid contact to hot and moving details as the engine at check should work.

Fuel hoses

Fuel hoses usually are under pressure therefore at their detachment be ready to that fuel will be sprayed and it is necessary for collecting.

Before serving fuel hoses, it is necessary to dump pressure in system of injection of fuel.

Check all rubber fuel hoses on existence of signs of wear and attritions. Pay special attention to sites of a bend and in front of unions, for example a hose junction with the fuel pump or the filter, cracks there can be formed.

Use only high-quality fuel hoses. Never, under no circumstances do not use as fuel not reinforced vacuum hoses, transparent plastic tubes or water hoses.

For fastening of fuel hoses collars of tape type are usually used. These collars weaken over time a tension and can "jump out" at removal. At replacement of hoses replace such collars with collars of screw type.

Precisely it is difficultly to define leakages of fuel, while leak does not become essential and, therefore, easily visible. Fuel tends to evaporate quickly as soon as it contacts with air, especially in a hot impellent compartment. Small drops can disappear before you can define a leak place. If you suspect that leakage of fuel in the field of an impellent compartment takes place, then cool the engine and start it, while it cold, at an open cowl. Metal subjects are compressed when cooling, and rubber hoses tend to be weakened, so any leaks will be more obvious, while the engine heats up at start from a cold condition.

Metal lines

Between the fuel pump and system of injection of fuel sections of metal tubes are often inserted. Carefully check these tubes on existence of dents, twisting or cracks.

If it is necessary to replace section of the metal line, use only seamless steel tubes, since copper and aluminum tubes are insufficiently strong to resist to the vibrations caused by operation of the engine.

Check metal brake lines in places of their connection with the main cylinder and with a pressure or ABS regulator (if it is available) on existence of cracks or the weakened shtutserny connections. Any signs of leakage of brake liquid demand immediate careful survey of all brake system.

Hoses of system of hydrostrengthening of a wheel

Check hoses of system of hydrostrengthening of a wheel on existence of signs of leakage of the liquid, the weakened shtutserny connections and worn-out collars. It is necessary to replace proceeding hoses and worn-out collars.

Hoses of system of cooling

Leaks in system of cooling are usually found on white or colors of a rust to a raid in the area adjoining leak.

Carefully check a radiator and hoses of cooling liquid on инами, gaps and aging signs. Cracks are easier for finding if to press a hose. Pay special attention to collars which attach hoses to elements of system of cooling. Collars of fastening of a hose which were strongly tightened, can cause a gap or a hose puncture, leaks in cooling system will be result of that. Examine all hoses and surfaces of connection of hoses about leaks. If any problems of similar character with leaks are found, replace this component or laying.