Car noises: common sources, examples, solutions
A noise in a car can ruin anyone's day. Some noises may be caused by something minor, others could indicate a serious problem. If you have any unusual noise in your vehicle, It's always best to have it checked out to be safe. Mechanics deal with car noises daily. Here are some of the most common examples:• Drive belt and timing belt noises:
• Steering and suspension
• Exhaust noises
• Tire noise
• Drivetrain noises
• Engine noises
Drive belt and timing belt noises
A loose drive belt can slip causing a loud high-pitch squealing or screeching noise. Usually you can hear it when the engine is just started or when the steering wheel is turned to the limit in either side. It is a fairly simple job to adjust the drive belt tension, so it shouldn't cost you a lot when you take your vehicle to a mechanic. Driving with a loose drive belt can cause many problems, e.g. low battery charge, overheating, lack of power-steering assist, etc. Read more about a drive belt.
Drive belt tensioner
A timing belt works in a similar way as a drive belt and can produce similar noises. One thing is different, the timing belt can make a whirring noise when it rubs against the belt cover. If the belt is too tight or something is misaligned or not installed properly, it also can produce a similar noise. If noticed this type of noise after replacing a timing belt, have the installation of the timing belt re-checked.
Noises from the steering and suspension
Suspension and steering noises need to be checked out as soon as possible to be safe. When a suspension component such as a tie rod end or a ball joint is badly worn, it can separate, sometimes even causing the vehicle to lose control. If you hear a knocking or other noise from the front end or rear suspension, have it checked out. Here are a few examples of some of the suspension and steering noises.
Sway bar link
The sway or stabilizer bar is a part of the front and rear suspension. A bad sway bar link can cause knocking that is more noticeable when driving slow over small bumps. Worn out sway bar bushings also can cause a similar knocking or thumping noise. Either part is not very expensive to replace.
Top strut mount
A bad top strut mount bearing could cause a clunking or popping noise coming from the front end while turning the steering, even when the car is stationary. It may feel like something jams and then releases when you turn the steering.
Bad steering shaft universal joint (u-joint)
A bad steering shaft universal joint (u-joint) can cause a clunk in the steering column while turning. An excessive wear in the steering rack can also cause similar noises.
The repair depends on the defective part.
Low power steering fluid level
Exhaust heat shields
Many parts of the exhaust are protected by heat shields. Over time, heat shields rust and become loose. Loose exhaust heat shields are the common source of metallic rattle. Usually, the rattling noise comes from underneath the car. It might be louder at certain engine RPMs. Usually, the rattling noise comes from underneath the car. Play the video to see how it sounds. It might be louder at certain engine RPMs. This type of noise is easy to repair: the loose heat shields need to be re-secured.
This type of noise is easy to repair: the loose heat shields need to be re-secured. This is one of the ways how it can be done.
A worn out front outer Constant Velocity joint or CV joint will typically produce a clicking or popping noise when driving through turns, especially with acceleration. Usually the CV joint goes bad after the CV boot is damaged (in the photo). In most cases, a whole drive shaft will need to be replaced and it could cost a few hundred dollars. Read more about CV joints.
A bad wheel bearing causes a humming or growling noise that gets louder at a certain speed. Often, a wheel bearing humming noise gets louder when turning to one side (e.g. when changing lanes) and quiets down when driving straight or turning to other side. Replacing a wheel bearing is a few hundred dollar repair. Read more about a wheel bearing.
An engine has a lot of moving and rotating parts and it can produce a variety of noises. Most of the internal 'mechanical' noises in the engine are usually caused by lack of lubrication, so checking engine oil should be the first thing to do with any internal engine noise. Here are few common noises:
A vacuum leak can cause a hissing noise that is noticeable at idle. Typically a vacuum leak can also cause the engine to run rough at idle or the engine RPM to be higher than normal. Look for disconnected or cracked vacuum lines or other sources of a vacuum leak.
The pinging or high-pitch metal knocking noise that is more pronounced under acceleration, especially when the engine is hot or under heavy load, could be caused by a detonation in the cylinders. The detonation, or as it's commonly known, 'spark knock', could happen for many reasons. Often using the fuel with lower than specified octane rating could cause the engine pinging or detonation. The excessive carbon build-up in the combustion chambers or too advanced ignition timing can also cause detonation in the cylinders. Sometimes when the engine runs too lean (more air less fuel), it also can produce a detonation knock, because the lean air-fuel mixture increases the temperature in the combustion chambers. A clogged catalytic converter can also cause the detonation or pinging. If your engine makes this type of noise, have the issue diagnosed before it can lead to more problems. Driving with a pinging engine can cause many serious (engine) problems including blown head gaskets, burnt valves and broken or burned pistons. See the photo.
A tapping noise that is coming from the top of a OHC or DOHC engine is often caused by lack of (the) oil pressure or worn out or out-of-adjustment valve train components. Again, check the engine oil level first. Sticking hydraulic lifters, which is a common problem in older OHV V6 and V8 engines, could also be the source of tapping noise. Some engine additives can help to free the lifters and get rid of the tapping noise.
The piston slap can cause a knocking noise, especially when the engine is started cold. It happens when the pistons are not perfectly tight in the cylinders. When the pistons are pushed up and down, the piston skirt 'slaps' against the cylinder walls. It's a fairly common issue in many cars. Sometimes an engine can run for a very long time with the piston slap noise without it causing any other issues. In other cases, an engine may require an overhaul to repair the issue.