3.20. Check of a state and replacement of hoses of a motive compartment, localization of leaks

Replacement of lines of communication of the air conditioning system has to be made at car repair shop, or in a specialized workshop where there is an equipment for safe dumping of pressure in system. Do not disconnect hoses of system at all and do not remove its components, previously without having dumped pressure!

General information

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

Additional information on hoses of systems of braking and cooling of the engine is provided in the Sections Greasing of Universal Hinges of Driveshafts and Check of Components of the Brake System respectively.


  1. For fastening of the majority of hoses on unions collars are used, - check reliability of their tightening providing due sealing of landing of a hose. In certain cases fastening of hoses collars is not provided, - make sure that the hose in the place of landing to the union was not inflated and/or did not harden, allowing leaks.
  2. In case of identification of signs of development of leaks any of working liquids which origin it is not possible to identify enclose a big leaf of a cardboard under the parked car and later rather long time study its state, - on color and location of potek it is possible with high probability to define the nature and location of leak.

Vacuum hoses


  1. It is easy to distinguish usually vacuum hoses which are especially applied in systems of decrease in toxicity of the fulfilled gases on bright color marking. In various systems hoses with various thickness of walls, thermal stability and resistance to a collapse are used, - when replacing hoses you watch that the new hose corresponded on the standard size and execution which failed.
  2. Often, the only reliable way of assessment of a condition of a hose is its removal from the car. At removal more than one hose take care of drawing the accurate marking providing unambiguity of their connection at installation into place.
  3. When checking vacuum hoses do not forget to estimate also a condition of T-shaped plastic nipple connections, examining them on existence capable to cause development of leakages of cracks.
  4. Remember that unevenness of deformation of a hose when landing to the union can give it to development of losses of depression.
  5. Leaks in vacuum lines are meant as the fact of a podsasyvaniye in them of air, i.e., air podsasyvatsya in a hose, but does not come out it that considerably complicates the procedure of localization of the defective site. For identification of places of violation of tightness aurally it is possible to use a small piece of the same vacuum hose as a stethoscope. At the engine started on single turns listen to all vacuum hoses and places of their connection of connection on existence of the characteristic hissing demonstrating existence of leak, - try not to burn about the hot surfaces of the power unit and do not touch moving elements in a motive compartment (a krylchatka of the fan, driving belts, etc.).

Fuel hoses

At survey or service of components of fuel system it is necessary to observe certain precautionary measures. You perform all works in well aired room, do not allow approach to the venue of works of naked flame (for example, the lit cigarettes) or the carryings unprotected by the lamp shade. Immediately collect the spilled fuel by rags, putting it then to the place where the impossibility of its spontaneous ignition will be guaranteed. At hit of fuel on open parts of the body immediately wash away it a plentiful amount of water with soap. Do not forget to put on goggles, always hold near at hand the fire extinguisher!

Fuel usually is in a path of a power supply system under pressure therefore at a detachment of hoses take measures against fuel spraying.

Before starting service of components of a fuel path, it is necessary to dump pressure in system of injection of fuel!


  1. Check all rubber fuel hoses for existence of signs of wear and attritions. Pay special attention to a condition of bends and sites of an adjunction to nipple sockets (the fuel pump, the filter and so forth).
  2. Apply only high-quality fuel hoses. Under no circumstances do not use as fuel not reinforced vacuum hoses, transparent plastic tubes or hoses of a cooling path.
  3. Collars of tape type which effort of tightening weakens over time that is accompanied by danger of "soskakivaniye" of a collar at removal are usually applied to fastening of fuel hoses on unions, - be careful. When replacing hoses such the collar will be reasonable to be replaced worm. Or screw.
  4. At the initial stage of development localization of leaks in a path of a power supply system is a difficult to achieve task, - fuel tends to evaporate quickly at contact with air, especially in the warmed space of a motive compartment. At emergence of suspicions on existence of leak of fuel in a motive compartment let's the engine cool down completely, then start it and attentively examine all available fuel-supply lines, - compression of metal unions when cooling leads to weakening of landing to them of rubber hoses that leads to increase in intensity and - as a result - to simplification of localization of the leaks taking place.

Metal lines of paths of the brake system and power supply system


  1. On sites of the working highway of a power supply system between the fuel pump and system of injection metal tubes which also should be examined attentively are often inserted, checking for existence of deformations, twisting, cracks and other mechanical damages.
  2. For replacement of defective sections use only seamless steel tubes, - copper and aluminum tubes do not provide the due resilience to impact of vibrations, arising during the operation of the engine.
  3. Check metal brake lines in places of their connection to GTTs, the regulator of pressure or the ABS hydromodulator (at the corresponding complete set) for existence of cracks and signs of weakening of nipple connections. Identification of any signs of leak of brake fluid demands immediate complex survey of all brake system.

Hoses of system of hydrostrengthening of a wheel


  1. Check hoses of system of hydrostrengthening of a wheel for existence of signs of development of leak of liquid, weakening of nipple connections and wear of fixing collars. Replace defective components.

Cooling system hoses


  1. Leaks in the cooling system usually are found by training violations of tightness of a raid of white or red-brown color in places.
  2. Carefully examine a radiator and a surface of hoses of a cooling path on all their length. Replace defective components.

Cracks come to light when tightening a hose easier. Pay special attention to a state and reliability of tightening of collars of fastening of hoses to connecting branch pipes of elements of the cooling system. Pulling of collars is accompanied by risk of formation of cuts and ruptures of hoses.