You have just driven out of your car park and suddenly you hear a noise you haven’t heard before. Your heart sinks. But it might not be as bad as you think. Modern cars, 4x4s, and vans are complex, but they are also very reliable and most modern cars normally signal a failure before a major repair bill looms.
Whilst some noises are merely irritating, others indicate something is seriously wrong. We offer the following as a musical diagnostic tool.
Clunking
When starting off or braking, clunking noises could mean a loose engine mounting or exhaust. When turning, it could be a drive shaft or suspension problems.
Squealing
Have the kids been fed? If squealing happens when you start the engine, it probably means a loose or faulty fan belt. If it happens when you use the brakes, it could mean the brake linings or pads need replacing. Squealing from the wheels, especially when turning or cornering, usually means that the air pressure in the tyres is low.
Whining or grinding
This sound in the gearbox or drive axle can point to a low oil level (needs urgent attention) or worn gears and bearings. If the grinding happens when you use the brake pedal, it indicates the brake pads or shoes are completely worn and are running metal-to-metal (immediate attention required).
Roaring
If the sound gets worse when accelerating, it probably means a damaged exhaust or exhaust manifold.
Hissing
If hissing happens when you stop and appears to be coming from under the bonnet, it is usually a sign that there is a leak in the radiator or water hose.
Spluttering
This is a tip-off that the engine is not getting the correct amount of fuel. The fuel tank could be empty or the fuel supply pump or fuel filter clogged. Sometimes it is an indicator of ignition lead or spark plug problems.
Pinging
When accelerating or going up a hill, pinging indicates the wrong grade of petrol has been used and a higher octane rating is needed, or the ignition timing is wrong.
Popping
A soft popping noise, together with a rough engine idle, could indicate a suspect valve or ignition timing. If the motor misses under load, e.g. when accelerating, it may be defective ignition leads or spark plugs. A louder popping during speeding up or slowing down is often a sign of wear in the exhaust silencer or a leak at the exhaust joints. It might also indicate a leak at the carburettor to the induction manifold.
Clicking and tapping
A light clicking or tapping could mean the tappets need adjusting, but a deeper and heavier engine knock is more serious and tells you that a connecting rod bearing (big end) or piston and piston connecting rod (small end) are failing. These signs need urgent attention.
www.aa.co.nz
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written by ulian, April 15, 2011
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