Chapter 9 Vehicle Maintenance, Fluid Service, and Recycling 151 Copyright Goodheart-Willcox Co., Inc. Fluid Leaks Fluid leaks result from bad gaskets, seals, or hoses cracks in parts and similar troubles. Leaks are very common problems that should be corrected. See Figure 9-22. To become good at leak detection and correction, you should: • Become familiar with the color, smell, and feel (texture) of the different fluids. Then, you will be able to quickly identify a fluid leak. Does the fluid feel more like water or oil? Dab a white paper towel into a puddle of fluid to show its color more accurately. Oil will be slippery to the touch and will be dark brown or black if used for an extended period of time. If the fluid is clear or brown and feels “squeaky” when rubbed between your fin- gers, it is probably brake fluid or hydraulic clutch fluid. Antifreeze can be green, orange, or rust colored and will feel slick. Automatic transmission fluid can be dark brown, red, or dark green. Power steering fluid can be amber, red, or clear and will feel like transmission fluid. • Fluid leaks tend to flow downward and to the rear of the vehicle. For this reason, look for leaks above and slightly in front of where you find fluid dripping off the vehicle. • If multiple leaks are indicated, fix the leak located the highest and farthest forward on the vehicle. Then, repair other leaks. • If the leaking part is badly soiled, clean the area thoroughly. Then it will be easier to see fresh fluid leaking out of the part. • The most frequent cause of fluid leakage is broken gaskets and worn seals. Replacement will usually correct the problem. However, you should always check the parts for warpage, cracks, and dents. Noise Detection and Location Abnormal noises are unwanted sounds that indicate part wear or other mechanical problems. They are common to almost all systems of a vehicle. When test-driving or idling the engine in the shop, listen for unusual sounds (knocks, clunks, rattles, clicks, and hisses). Locating the source of these sounds will help you identify problems that might not trip a trouble code. A stethoscope (similar to that used by a doctor to listen to a patient’s heart) is commonly used by an auto technician. It will help the technician pinpoint the source of internal part noises. To use the stethoscope, touch the probe on the component near the unwanted sound. Move the stethoscope around until the sound is the loudest, Figure 9-23. A long screwdriver can be used in place of a stethoscope. Place the tip of the screwdriver on the part. Place the handle next to your ear. Sound will travel through the screwdriver and permit noise diag- nosis. Make sure you keep the screwdriver away from moving parts or you could be injured. A section of vacuum hose is a handy device for finding sounds not coming from internal parts. The hose is useful for locating hissing sounds, rattles, whines, and squeaks. Place one end of the hose to your ear. Then, move the other end around the area of the sound. When the sound becomes the loudest, you have pinpointed the problem. Again, keep the hose away from moving or hot parts. By removing the metal end from a stethoscope, you can also listen for these kinds of noises, especially hissing vacuum leaks. Goodheart-Willcox Publisher Figure 9-22. When working under a vehicle, always look for signs of fluid leakage and other obvious problems. Inspect rub- ber boots and hoses for signs of damage.