Diagnosing car noises

We often receive questions about what can cause one or the other noise in a car or truck. Of course, it's very difficult to diagnose the noise without even seeing a vehicle. Sometimes, even when you take your vehicle to a mechanic, it may take a lot of time to find the source of the noise. To help you with diagnosing the noise, we decided to describe few common noises and their sources in a car or truck. 

Of course, If you have any irregular noises in your car or truck, It's always best to have your vehicle checked out to keep it safe. Don't forget to bookmark this page for future reference!

Drive belt and timing belt noises

Drive belt

 A loose drive belt can slip causing a loud high-pitch squealing or whistling 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 should not cost you a lot when you take your vehicle to a mechanic. Driving with a loosened drive belt can cause many other problems, e.g. low battery charge, overheating, lack of power-steering assist, etc. 

Drive belt idler

 A worn-out drive belt can cause chirping or squeaking noise that is usually more noticeable after driving in the rain. This happens because the water gets on the belt and washes off the dust. This type of noise can also be caused by misalignment of the belt pulleys. Have the drive belt checked, it's not an expensive part to replace.

A worn-out bearing inside the belt idler or tensioner or can cause a whining or buzzing noise. A bad bearing in the alternator also can cause a similar noise.

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 or whining 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 after replacing the timing belt you get this type of noise, have the installation of the timing belt rechecked.

Engine noises

Car engine

 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.

 

Piston with a connection rod

 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 pinging engine can cause many serious engine problems including blown head gaskets, burnt valves and broken or burned pistons. See the photo. 

Pistons can break as a result of detonation

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. Sometimes an engine may require an overhaul to repair the issue.

Excessive wear in the crankshaft main bearings can produce a heavy knocking or thumping coming from the bottom of the engine. Sometimes, the main bearing noise can go away when the engine is revved. Sometimes it can be more pronounced when the engine is decelerating.

The connection rod bearing noise also sounds like heavy knocking coming from the engine block. Typically the connection road bearing noise gets louder when the engine is accelerated. The crankshaft bearings are lubricated by engine oil and most of the time, problems with crankshaft main bearings or connection rod bearings are caused by lack of lubrication. It could be a result of low oil level, clogged oil pick-up screen, low oil pressure, poor quality oil, lack of oil changes etc. Both, the connection rod and crankshaft main bearing knock typically requires a complete overhaul of the engine. 

Exhaust noises

Exhaust manifold

 

 

 

A leaking exhaust manifold can cause a ticking or tapping noise, which is typically louder when the engine is started; the noise could also be accompanied by the exhaust smell from the engine area. Usually this type of noise disappears or quiets down after the engine runs for a few seconds. The exhaust manifold leaks are usually caused by broken manifold studs or cracks in the exhaust manifold.

An exhaust heat shields are the common source of metallic rattle with the engine running. Usually the rattling noise comes from underneath the car and intensifies at a certain engine RPM. This type of noises is usually easy to repair: the loose heat shields are typically secured with worm gear clamps. 

Steering and suspension noises

Outer tie rod end in a front-wheel drive car

 

Suspension and steering noises also 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 steering or suspension, have it checked out. Here are few examples of the typical suspension and steering noises. Of course, there could be a lot more problems in the suspension and steering that can cause various noises. Any noise should be properly diagnosed.

 

Stabilizer bar link

 

A bad tie rod end usually causes a rattling or knocking noise from the front end when driving slow over small bumps or rough road. After a bad tie rod end is replaced, the wheel alignment procedure must be performed.

A stabilizer bar link can cause a similar type of noise. It may sound as a not very loud knocking when driving slow over small bumps. Worn out stabilizer bar bushings also can cause a similar noise. Either part is not very expensive to replace. 

Lower ball joint

A bad ball joint can cause a clunking or knocking noise coming from the front suspension. Depending on the design, a vehicle may have one, two, three or even four ball joints in one side of the front suspension. Sometimes, a ball joint comes as an assembly with a control arm. After the control arm assembly or a ball joint is replaced, the wheel alignment procedure usually needs to be performed. 

A bad upper 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. 

A bad steering shaft joint or lack of lubrication in the intermediate shaft splines in the steering 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 or air present in the hydraulic power steering system can cause loud moaning, buzzing or whining noise coming from under the hood when turning. The fix is to check the power steering system for leaks and repair if needed, add power steering fluid and bleed the power steering fluid system.

Drivetrain noises

Broken CV joint boot.

 

A bad front 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 joint 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

Front wheel bearing.

 A bad wheel bearing causes a humming or growling noise that gets worse with speed. It usually gets quite loud when driving on a highway. It's not always to diagnose a noisy wheel bearing, but here is a tip: the wheel bearing humming noise in most cases gets louder when turning to one side and quiets down a bit, when turning to another side. Replacing a wheel bearing is a few hundred dollar repair. Read more about the wheel bearing problems. 

A deteriorated oil in a limited slip differential could cause a clattering or chattering noise coming from the rear end during turns. For example, Honda CR-V is known to have this issue. A new oil of the proper grade usually can fix the noise. 

A problem with a rear differential can cause a humming or growling noise from the rear end that gets worse with the speed. Usually the rear differential will need to be rebuilt or replaced.

 

Tire noises

Cupped tire

 A cupped tire can produce a loud ramble or a growling noise that may sound like a bad wheel bearing. If you click the photo to see the larger image, you can see that the tire is not rounded along the tread. Its wear pattern has alternating flat and elevated spots. It's easy to feel it with your hand, moving it around the tread. Obviously this tire won't be quiet, especially at higher speeds. 

Cut Costs on All General Automotive Repairs

Owning a car exposes you to a myriad of challenges, not least the maintenance expenses you incur with the ownership of a car. And during these tough economic times, people are constantly on the lookout for ways to cut cost on automotive repairs, thus let us look at ways to accomplish just that.

The first step you should take is to check if your vehicle is still under warranty. If it is, then you could look to save quite a lot of money from making use of your warranty. Check if your warranty covers only parts or both parts and labour, and ensure that you read all the terms and conditions within your warranty agreement to make full use of it.

 

Be careful to take your vehicle only to authorized service centres as penned out in the warranty, and not to other workshops that would make you pay more as it is not covered under your warranty. If you car is under warranty, it is advisable to take your car to the manufacturer’s own service centres as this would ensure that your get all the original parts installed as well as personalized attention from experts in the field.

If your car is not under warranty, you now have the option of choosing your own service centre to repair or service your car. To cut costs, you could avoid the manufacturer’s service centres and instead head to any established workshops out there.

You can also make do with OEM parts instead of the original manufacturer’s parts, as they would do the job almost as well, and they would prove to be much cheaper than the originals parts. A point to note before choosing your service centre though, make sure the mechanics are professionals and certified so that you do not get bad service for your car. Experienced mechanics would also be able to advise you on cheaper substitute parts for your cars to cut overall costs of automotive repair.

Another great option is by doing the repair works yourself. Remember not to fiddle with automotive parts and systems that you are not familiar with. This could prove to be extremely costly if something goes wrong. You could probably perform the smaller tasks such as changing the oil filter and changing the engine’s lubricant without having to take the car to a service centre. It would be best to buy a do-it-yourself car service handbook to help with these tasks, or you could also attend a short course on basic maintenance repairs to help enhance your knowledge on this topic.

For more major tasks, it is recommended that you take your car to the professionals, as you do not want to incur extra expenditure if something goes wrong. Follow the tips above to reduce costs on your vehicle’s repairs.

Reduce the risk of your engine overheating

An overheating engine can range from annoying and inconvenient to very dangerous. There are many causes of overheating which need to be assessed carefully to establish and resolve the problem.  

Here are some tips to help you reduce the risk of your engine overheating:

• The most common cause of overheating is to do with defects or problems with the cooling system. Have your cooling system serviced regularly and your coolant fluid checked
• Another common cause of overheating is lack of water in the engine. This can cause the car to smoke, time out or even the engine to blow
• If you do have an overheating problem get your engine inspected as soon as possible before getting back out on the road
• Overheating can damage the engine and your car may need repairs before driving again after it overheats
• Always monitor the temperature gauge carefully when you are driving
• Check your car for leaks
• Regularly change the oil and water
• You should only add water to the engine when it is cold

In the case that you do have an overheated car there are some precautions you need to take when dealing with it to ensure your own safety:

• Do not continue to drive if your car is overheating, this is extremely dangerous
• Never open the radiator cap on a hot engine. You could get severely burnt
• Pouring cold water into or onto the engine might cool things down but it won’t solve the problem. After you have experienced overheating seek professional advice
• Check the coolant levels and water levels once the engine has cooled down. If your coolant is low replenish it
• Check for leaks in the coolant system, this could be causing the problem
• Only use one type of coolant and always use the right coolant for your car
• You car’s thermostat should be in good working order, after an overheating incident this may need replacing

The best way to avoid overheating is to take good care of your engine and get regular check-ups. Fix any problems as they happen and get the car sorted after an overheating incident. Overheating can cause accident and injury so it is best to take measures to keep you and other road users safe by looking after your engine.

Car Maintenance 101

Part 1 – Basic Car Maintenance 

If you want your car to last longer, get you where you need to be and keep you safe then you need to return the favour and give your car the care it needs. 

As little as 10-20 minutes a month could save you time and money when it comes to your car.  Simple checks on your cars basic running systems that you can do yourself will reduce the risk of breakdowns and damage to your vehicle. 

Here are some useful tips to get you started;

1. Tyres – your cars tyres are what keep you on the road. Every month check the pressure of your tyres. The right pressure can be found in your vehicle manual, if you are unsure ask an expert. Check for wear and tear and check that the tread is not too worn down. Tread should be no less than 1.5mm across your tyres. Look for any damage that may have been done to your tyres and if you are unsure about safety issues check with your mechanic. 
2.  Oil – This is a good indicator of the internal health of your car. Check your engine oil once a month. If the car is churning through oil at a rapid rate this is a sign that things are not functioning well. Oil levels should be on or close to the high mark on your dipstick. The oil should be clean and clear, if it is dirty it needs changing. You might also need to get your oil filter changed. Lack of oil in a cars engine leads to unnecessary wear and tear on the engine.
3. Cleaning – cleaning your car on a regular basis will help with its long term sustainability. Washing and polishing the exterior of your car helps prevent rust and general wear and tear. Cleaning the interior also helps to maintain the fabric and panels. Always use the right cleaning products on your interior.
4. Brake Fluid - Checking on the levels and colour of your brake fluid can help you to catch problems with your brake system before they get serious. Brake fluid should be clean and at an appropriate level. If you need to top up ensure you use the correct fluid for you car. If your fluid looks dirty contact a mechanic to get a professional assessment.
5. Drive with care – the way you handle your car does have an effect on its condition. Take care with your steering, brakes and handbrake, all of these can be costly to repair. Take it easy when driving on uneven surfaces and going over speed bumps. Stay alert when you are driving so you can pick up irregular sounds and notice changes in the way the car runs. If you can catch things early you can prevent costly damage.
6. Always follow the maintenance and service recommendations found in your vehicles manual.

Spend a little time each month checking on the health of your car and you will save time and money in the long run. 

The Importance Of Gear Oil & Why You Should Take Care Of It

 

Amongst mechanics, there seems to be two schools of thoughts regarding gear oil. While some recommend that you change gear oil at regular intervals, others do not bother too much about it at all. Whatever it is, gear oil is definitely the most neglected item of a car.

What in reality, is gear oil? Gear oil is motor oil that’s made specially for the transmission or the differentials in an automobile. According to my mechanic friend, Raman, unlike engine oil, “gear” oil is numbered 90W to 140W. This means gear oil, has a high viscosity. Its “thickness” is necessary to provide maximum protection which is so essential for moving parts of the gear boxes.

Gear oil is very similar to motor oil or, if you like engine oil, which is used for engine lubrication. Gear oil, on the other hand, possess many different properties. This is to meet many different demands that are placed on it.

Unlike engine oil, gear oil takes a great of deal heat, without breaking down. Its duty is to lubricate other parts in an engine. However, gear oil does not reach the temperatures of an engine oil.

Gear oil, is associated with parts that move somewhat slower. Nevertheless, it is reported to get heated up significantly as the vehicle is driven. In gear boxes or differentials, pressures in interlocking metals are said to be more extreme. Because of this, gear boxes require the assistance of gear oil.

What does gear oil contain? It contains sulphur. Sulphur forms a protection coating on all metal parts it touches. This will prevent direct metal to metal contact. Without the coating provided by gear oil, extreme pressures which takes place in the gear box, the parts inside would heat up to a temperature that is considered as hazardous to the operating capability of vehicles and parts will eventually wear out.

Gear oil in passenger vehicles, it is not something that is frequently replaced by motorists, unlike engine oil. For those of you riding motorcycles, it is recommended that you change your gear oil every 3,800 miles or 6,000 km. Do remember, that a motorcycle gear will deplete as time goes by. It then loses its ability to protect the clutch as well as the gear systems of a machine.

How does one go about changing the gear oil of a vehicle?

The same applies as to changing the engine oil. For cars, simply drain oil from the differential, then replace the drain plug, pour in the required amount, which is anything from 3.5 litres to 4 litres, and then replace the oil lid.

In the case of motorcycles, replace with oil that is specially intended for motors and scooters duly. For readers’ information, I use a very popular gear box oil currently available in Malaysia. It is American made. Among the properties of the above oil are:

1. it is suitable for all manual transmission.

2. Quietens noisy operation of gear boxes.

3. Restores smooth shifting of gears.

4. Improved performance is guaranteed.

Finally, it should also be made known that the above gear oil, used by the writer is the only lubricant company in the world ever to be inducted into the Space Foundation Hall of Fame!

Well then, what are you waiting for? Go for it! And in doing so, I hope you’ll enjoy easy and smooth changing of gears.