Diagnosing Car Noises
Common Car Noises And What They Mean
We grow accustomed to the way our engines sound after a certain period, so when you start hearing strange noises coming from the engine bay, wheels and suspension components, it is your car asking for your attention. Strange sounds are an indication that some components within your car have failed or are about to break. As components and systems within the vehicle fail, they start to show signs of failure which can be observed visually and in many cases through sound. As your vehicle ages, strange noises are bound to emanate from different parts of the car. But do not ignore these noises as they can help you indicate which system is at fault and carry out repairs accordingly.
Here we have compiled a list of strange sounds that commonly occur in cars and what they indicate. The sounds include screeching, squealing, grinding, hissing, ticking, clunking, clicking, or other similar noises and can originate from different parts. Note that different noises can be perceived differently by different people so make sure you isolate the area where the sound is coming from before proceeding with any repair.
In this article:
Screeching
From Brakes
A screeching sound coming from the brakes can mean a few things. Either you have worn brake components like worn brake pads or faulty brake rotors, or you may have some excess brake dust, surface rust, or water on the brake disc surface. Leaving your car overnight in a snowy or wet area can cause the brake rotors to develop surface rust. As you drive your vehicle in the morning, this surface rust gets ground and creates a screeching or squeaking noise on brake operation. This is considered normal and should fade away as the brakes get warm and the rust is ground off unless you notice a considerable decline in performance.
If the brakes showcase a screeching, grinding, or squealing noise every time you push the brake pedal, it could mean that the brake pads are worn beyond their friction material and the metal backing plate of the brake pads is rubbing against the rotor. Some brake pads have metal wear indicators that create a similar screeching, squealing, or grinding noise upon brake operation. This indicates you need to replace your brake pads immediately.
From Wiper Blades
Squealing Or Squeaking
A loud squealing noise is commonly presented by the accessory belts as you start your car. This squealing or whining noise can be caused by a faulty accessory belt, bad belt tensioner assembly, oil leaks or a broken idler or accessory pulley bearings.
Faulty Serpentine Belt: An overly tight, loose, misaligned or worn-out serpentine belt can create a squealing noise. The serpentine belt powers various components in the engine that run off the car’s engine torque like the power steering pump, alternator and AC compressor. It can easily be spotted as the long snaking belt that wraps around the pulleys of these parts. Older vehicles have more than one belt, usually one belt per accessory drive. Check the tension and condition of the belt along with how it sits over all the pulleys. Cracks, tears and fissures on the belt or broken teeth or ribs mean the belt is severely worn and needs to be replaced. For in-depth diagnosing of serpentine belt failure, you can refer to this article.
Broken Belt Tensioner: The actual cause of the belt whine can be due to a bad belt tensioner assembly failing to provide enough tension on the belt to keep it taut or being overly tight. Readjusting the tensioner can fix this problem unless the tensioner itself is broken and needs replacing.
Worn-out Pulley Bearings: Worn-out bearings on the idler or accessory pulley can cause the belt to sit unevenly which leads to misalignment of the belt. To check if the bearings are bad, disconnect the belt and listen to each pulley by rotating it in its place. A grinding or squealing noise often indicates busted bearings.
Oil Leaks: If you see oil leaking onto the accessory belt from the engine, power steering pump or some other part, then you will have to first fix the leak as that is likely the cause of the squeal.
Grinding
From The Wheels
If you hear a grinding or humming noise coming from the wheels at low or high speeds, then you can have problems with the wheel bearings or the CV joints. A worn-out wheel bearing within the wheel hub assembly can also cause the wheel to vibrate and misalign the CV joint which can create further issues. A grinding noise from either of these components can be dangerous as it can result in driveability problems. Remove your tire and inspect the wheel hub and CV joints. A tear on the CV joint boot can mean contaminants made their way into the joint creating excess friction and damaging the joint. This will warrant a complete CV joint replacement to restore functionality.
To check the wheel bearing on the hub, try rotating the wheel hub and listening to the sound. The rotation of the hub should be smooth and noiseless, otherwise, you will need to replace your wheel hub. With the wheel attached push the wheel back and forth without rotating it, any play can also indicate shot bearings. Here's how you can diagnose and fix wheel bearing troubles.From The Transmission
Hearing grinding sounds as you change gears? This means the clutch does not completely disengage either due to lack of complete clutch pedal depression or because the clutch plate has worn out. In some cases, it is possible that the sounds may be coming from the transmission due to a fault inside it. The job of finding and fixing issues with the clutch and transmission is better left to the pros so contact your mechanic for further assistance.
Hissing
From The Engine Bay
You may hear a hissing sound coming from the engine bay for two reasons:
Pressure escaping from the hot cooling system: If there is a leak in the cooling system, hot coolant escaping from a small orifice can create a hissing noise. Since the coolant within the system is pressurized, hot coolant or steam forcing out of a small crack, hole or partially open radiator cap can emulate a hissing sound. The sound may be faint but can continue after the engine is shut off until the pressure within the cooling system is relieved. If the coolant within the radiator reaches maximum pressure, which usually happens when the engine is overheating or if there is low coolant, the radiator cap releases the excess pressure and can be heard as a hissing sound.
If the hissing sound is coming from the radiator cap, then check the coolant level and top up if necessary. Do not touch the radiator cap with bare hands as it can be seriously hot. If the sound appears from a different part of the cooling system such as the radiator core, radiator hoses, water pump, thermostat, or heater hoses, then you may have a leak in that part due to a blown gasket or worn hoses causing the hissing. There may also be visible coolant leaks from the same area.
From The Exhaust
Clunking
From The Suspension: The suspension is made of many interconnected parts that are designed to move with one another. Several bushings are found in the suspension system connecting various components like the control arms, sway bar, sway bar links, subframe, etc. Since these bushings are under a lot of stress, over time they tend to tear and disintegrate. This causes metal-on-metal contact which creates clunking or rattling noises. Such noises may be more apparent when going over bumps or making turns. Clunking, ratting or tapping noises can also appear due to broken ball joints in the tie rods, sway bar links and control arms.
Groaning
From The Steering: If you hear a loud groaning or whining noise and have trouble turning the steering wheel, then you may have some issues with the power steering system. Low power steering fluid in the system is the typical cause for this noise. A leak in the system can cause low fluid levels and can also introduce air into the system which can damage the power steering pump and create strange noises on operation. Refill the power steering fluid or replace it if it is in very bad condition and also fix any leaks to eliminate the annoying sound.
Clicking
Hearing a repeated clicking sound while trying to start your vehicle can mean you have a dead or failing battery. Whereas hearing a single click when you turn the key in the ignition can mean you have a bad starter that is not working. The click you hear is from the starter relay switching on. Repeated clicks indicate the battery is too weak to power the starter motor. You can check whether your battery is in good condition and can be recharged or needs replacement using this article. If your battery is in good condition, then the starter is likely preventing vehicle startup and needs to be looked at.
These are just some of the many weird and annoying sounds that you may hear from your car. The above-mentioned sounds are some of the more common ones that most people encounter as their vehicle ages. Every unusual sound you hear can point to a system or component malfunction urging you to service your car before things get worse. Obviously, if you want to minimize such sound occurrences then make sure you service your vehicle regularly and replace all the car fluids according to their replacement intervals.
Back in the day, when electronic diagnostics were not so prominent or efficient, visual aid and hearing clues were the best approaches for diagnosing issues in your car, and many of these still hold up today. Remember to get your vehicle looked at by a professional if you are unable to understand or locate the source of any sound. Do not ignore these noises as they can end up costing you more in the long run.
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