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Various noises may indicate a serious problem with your car. Check it out!
Contents |
Locating
Grab a long screwdriver and place it on the top of the idling engine then put the handle up against your ear. Move the tip of the screwdrivers around till you can hear clearly what the noise might be (this works like a stethoscope). In this way you can usually pinpoint the location of the noise, down to front of engine, top of engine, exhaust of engine etc.
Also try the same 'stethoscope' approach using a rubber hose. Large 15mm hose can help locate the general area, and small 8mm hose can help pinpoint it.
Listen underneath the car to hear if it is louder possibly indicating bearings problems on the crank or conrods. If it is softer underneath the car and louder at the cylinder head, then valvetrain noise is more likely. Timing Chain noise is usually loudest near the water pump.
Hissing, Flappig and Airy Noises
Vacuum Leaks
Squeaking, Squealing
Causes of squeaks and squeal may include:
Fan belt loose or glazed Water pump bearing worn
Tapping, Knocking
Tapping/ticking is a light sound. By contrast Knocking is a heavy/deep/hollow sound. However pinging is also called spark knocking but is a rattling sound under slight or heavy acceleration.
Spark Knocking
A light metallic rattle from the engine while accelerating is bad.
Knocking
The classic repetitive/regular knocking sound is worn main bearings (worn rod bearings make a tapping sound).
A loose flywheel also makes a dull knocking sound.
Tapping
Worn rod bearings make a distinctive tapping sound (worn main bearings make a repetitive/regular knocking sound). Rod bearings which are worn are often only heard when lightly accelerating but with more wear may be heard at all times. By contrast knocking mains may only be heard on acceleration.
A cracked exhaust manifold -- or a leaking manifold flange -- sometimes sounds exactly like a noisy tappet.
Engine valves are the most common source of ticking/tapping/clicking sound -- if not adjusted properly or if worn.
IF it is a tapping sound more than a knocking sound, set the valves which is supposed to be done yearly in any case. Be sure to use the two-leaf method to ensure the correct tightness -- even two-thousands of an inch off will be noisy. Remember, the valves loosen up when the engine warms up.Timing Chain can be heard loudest near front cover or when the oil cap is removed.