Tuesday, June 12, 2012
Car Care: troubleshooting exhaust problems
[Article copyright by Ewe Paik Leong]
Noise caused by a faulty exhaust system should be distinguished from that caused by a mechanical problem with the engine.
If the noise is present when the vehicle is idling and gets louder when the accelerator is depressed, the source of the trouble is the exhaust system. On the other hand, the noise occurs only when the vehicle is moving, the culprit is likely the engine.
A hollow roar means there is a hole in one of the exhaust components. A hissing or puffing noise indicates a crack in the exhaust manifold or a leak in the gasket. If the noise louder when the bonnet is open, the problems lies with one of the exhaust components near the engine.
A blockage in the exhaust system, usually in the pipe or catalytic converter, produces a chugging or choking noise. A rattling noise can mean that a misaligned system is touching something under the car or that the baffler is loose in either the muffler or resonator. A rattling noise can also be caused by a broken catalyst lying somewhere in the components of the system.
A loose clamp or hanger produces a loud metallic vibration, but such a noise can also be caused by something coming in contact with the exhaust pipe. If the metallic vibration is muffled, comes from the back of the car, and changes in pitch with varying engine speeds, the problem likely is with a broken baffle in the muffler.
Blue smoke shows that engine oil is being burned; black smoke, the fuel mixture is too rich to be burned completely. Steam from the tailpipe indicates a possible leakage in the engine coolant.