car noises

Unnatural noises and their nature:

     Noises often indicate some sort of malfunction and need to be addressed promptly to avoid further damage to the car or potentially hazardous situation on the road. We'll attempt to tell you about the kind of noises there are and what they mean, however, usually any noise that you aren't sure about

What kind of noises are there and what causes them?

     We'll attempt to tell you about some noises and their possible causes. Any noise requires quality mechanical inspection to ensure that nothing serious is damaged or broken, which can lead to potentially hazardous situation.

Pinging/Ticking

     If pinging occurs at fixed intervals or increases as the engine RPM's increase, then this indicates sticky or worn valve or valve lifer. Basically this mean that the engine is worn and should be avoided.

     Sometimes ticking can be caused by a stone stuck in the tire or a loose hubcap.

Knocking

     Knocking coming from the engine indicates potentially serious problems. Avoid such car. If knocking comes when you turn the steering wheel, this indicate suspension components wear and can be quite costly to diagnose and fix.

Thumping

     Thumping from the rear in rear wheel drive car indicates worn rear axle and suspension components. Avoid such car. Thumping in the front might indicate loose front suspension components or tires and is a potential safety hazard. If the car loudly thumps when you put the car in gear in automatic transmission, this indicates automatic transmission wear.

Hissing

     This usually indicates vacuum leak somewhere in engine's system. This can take time to diagnose and depending on the problem can be as simple as replacing a clamp to as complex as replacing major gasket on the engine. Avoid the car if you hear hissing or see an increased idle speed (normal idle speed at normal engine temperature is about 750rpm). If the car has a turbocharger, some hissing sounds are normal (when the turbo spools up and when you shift gears).

Grinding

     If the car has a manual transmission, grinding during shifting usually means worn inner transmission components.

Backfire

     The car has misadjusted balancing of fuel-air mixture or a range of other problems and you will have to take it to a mechanic to diagnose the cause.

Squeak

     Squeaks over bumps usually indicate worn shock absorbers. It's more common on older cars. Replacing all 4 will cost quite a bit. Squeak when breaking indicates worn break pads or glazed pads, which essentially means that you will have to take the car to a mechanic to get it checked out. Squeak while going straight might indicate bad wheel bearing or warped rotors, All of these problems cost quite a bit to diagnose and repair.

Scratch

     Scratching noise or grinding scratching noise when breaking most likely means completely worn brake components, which require immediate replacement, as they are safety hazard. Scratching noise while driving can mean anything from tires scratching the wheel well to bad wheel bearings to bent axels. 

Conclusion:

     A car in perfect condition should not have any unusual noises coming from anywhere. It should operate silently, for the exception of normal engine sound and normal tire-on-the-pavement sound. Any of the noises listed above should alert you that there are problems, potentially serious problems, associated with the car. If you still want to buy it, it's best to get it checked out by a mechanic or avoid it altogether.