The recommended frequency: each 12 000 km of a run or 6 months.
You make replacement of hoses on the air conditioning system at the service station having the equipment for check and gas station of system.
High temperature serves as the reason of deterioration in properties of rubber and plastic hoses in a motor compartment. Periodic survey has to help to reveal cracks, the weakened fastenings, local hardenings and leaks.
If there were signs of leak of any liquid, but you cannot define its type or the exact place of leak, it is necessary to enclose at storage of the car under it a big piece of paper or fabric. It will help to find the place of leak and to identify the following liquid on color. But keep in mind that some leaks can appear only at the working engine.
At violation of tightness of a vacuum hose air is sucked in in a hose (but does not leave a hose) that complicates leak detection. For definition of leak it is possible to use an old vacuum hose as a stethoscope. Apply one end of a hose to an ear (do not insert into an ear), another — to the place of alleged leak. In the place of leak through a hose the hissing sound will be clearly heard. As check is carried out during the operation of the engine, avoid contact with hot and moving details.
To precisely define the place of leak of fuel can be difficult until leak does not increase and will become noticeable. Fuel begins to evaporate quickly as soon as it contacts with air, especially in a hot motor compartment. Small drops can disappear before you define the place of leak. If there is a suspicion that the place of leak of fuel is in area of a motor compartment, let's cool down to the engine and bring him at an open cowl. As metal details decrease in sizes in a cold state, and rubber hoses are weakened at this time, any leaks will become more noticeable at this time.
Leaks in the cooling system usually are found on a raid of white color or color of a rust in the field of leak.
Carefully check a radiator and hoses of cooling liquid on all length. Replace hoses with cracks, gaps and signs of aging. It is easier to find cracks if to press a hose. Pay special attention to collars of fastening of hoses to cooling system elements. Strongly tightened collars can become the reason of a gap or a puncture of a hose that will lead to leaks in the cooling system. Examine all hoses and places of their connection. If leaks are found, replace them or the corresponding laying.
On cars with the automatic transmission check a condition of hoses of the heat exchanger of gearbox oil.