Caution: Replacement of the air conditioning system refrigerant lines must be performed at a service station or workshop with equipment for safely relieving pressure in this system. Never disconnect refrigerant lines or remove air conditioning system refrigeration components without first relieving the pressure.
General information
1. Exposure to high temperatures in the engine compartment leads to gradual failure of rubber and plastic hoses used in various systems. Hoses should be checked regularly for cracks, loose clamps, hardening of materials and signs of leaks.
2. Information regarding the cooling system hoses is provided in Section 4, and to the brake system hoses - in Section 8.
3. Most (but not all) hoses are secured with hose clamps. Where clamps are used, check that they are securely tightened to ensure there are no leaks. If clamps are not used, ensure that the hose where it connects to the fitting is not swollen and/or hardened.
4. If there are signs of any fluid leakage, but the type or origin of the fluid cannot be identified, leave the car for a long time and place a large piece of paper or rag underneath it. This will help to find the place where the liquid is leaking, as well as identify it by color.
Note: Some leaks may only become apparent when the engine is running.
Vacuum hoses
5. Typically, vacuum hoses, especially those used in emission control systems, are color-coded or have colored stripe inserts. Different systems require hoses with different wall thicknesses, heat resistance and collapse resistance. When replacing hoses, make sure that the material of the new hose matches the material of the old one.
6. Often the only reliable way to check the condition of the hose is to completely remove it from the car. When removing multiple hoses at once, mark their ends and fittings to ensure proper reassembly.
7. When checking the vacuum hoses, be sure to also check the plastic T-joints. Inspect them for cracks that could cause leaks.
8. A leak in the vacuum hose means that air is being sucked into the hose (but it doesn't come out of the hose), and this makes the leak difficult to detect. To detect vacuum leaks, you can use a small piece of vacuum hose as a stethoscope. When the end of the hose is directly over the leak, a hissing sound will be clearly audible through it. Listen to all vacuum hoses and connections for a hissing sound indicating a leak.
Caution: When using this type of stethoscope, be careful not to allow your body to come into contact with moving components in the engine compartment, such as drive belts, cooling fan, etc.
Fuel hoses
Caution: Certain precautions must be observed when inspecting or servicing fuel system components. Perform all work in a well-ventilated area, do not allow open flames to approach (for example, lit cigarettes) or lamps not protected by lampshades to the place where the work is being carried out. Any spilled fuel should be immediately collected with a rag and then placed in a place where it cannot ignite. If fuel comes into contact with your skin, wash it off immediately with plenty of soap and water. When working on the fuel system, wear safety glasses and always have a fire extinguisher on hand.
9. Fuel hoses are usually under pressure, so be prepared to collect any squirting fuel when disconnecting them.
10. Check all rubber fuel hoses for signs of wear and tear. Pay particular attention to bends and in front of fittings, such as where the hose connects to the fuel pump or filter, where cracks may form.
11. Use only high quality fuel hoses. Never use non-reinforced vacuum hoses, clear plastic tubing or water hoses as fuel lines.
12. Band type clamps are usually used to secure fuel hoses. These clamps become loose over time and may "pop out" when removed. When replacing hoses, replace these clamps with screw type clamps.
13. Minor fuel leaks are difficult to pinpoint because fuel tends to evaporate quickly once it comes into contact with air, especially in a hot engine compartment. Small drops may disappear before the leak can be located. Metal fittings contract as they cool, and rubber hoses will be weakened so that potential leaks will be more obvious as the engine warms up when starting from cold.
Metal tubes
14. There are sections of metal tubing installed between the fuel pump and the fuel injection system and these should be carefully checked for dents, twists or cracks.
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15. If a section of metal line needs to be replaced, use only seamless steel tubing as copper and aluminum tubing are not strong enough to withstand vibrations caused by engine operation.
16. Check the metal brake lines where they connect to the master cylinder, pressure regulator/ABS hydraulic modulator for cracks or loose fittings. Any signs of brake fluid leakage require immediate and thorough inspection of the entire brake system.