There is a multitude of vehicles out there, perhaps more manufacturers, models and variants than ever before. Be it a Lamborghini or a Tata, most vehicles are designed and built using the same fundamental principles, which means that most vehicles will experience the same problems as they age.

Of course, there will be differences depending on your make and model, the choice of powertrain or transmission, and manufacturer-specific components or design choices which may cause their own troubles, but, when it comes down to the main elements and most basic systems, cars often need to go to the repair shop for the same reasons.

Certain auto parts simply need to be replaced more often than others, and as a car owner, you should anticipate and budget on having to replace the following components in the future. 

Here is a list of the top 15 most frequently replaced automotive parts.

Regular maintenance parts

1. Oil filter

No matter what type or model of vehicle you own, the part you’ll need to replace the most often is the oil filter. The lubrication system is critical to the proper operation of any internal combustion engine. Subject to your vehicle manufacturer, the design of your vehicle’s lubrication system, and the quality of oil used, you’ll need to get the engine oil and oil filter replaced yearly or every 10,000 km to 15,000 km.


2. Air filter

The engine air filter also requires replacement on a regular basis. Most vehicle manufacturers will recommend replacement yearly or every 15 000 km, but the real barometer of when to replace the air filter is when it becomes dirty or clogged. Driving frequently on gravel roads will greatly shorten the lifespan of your air filter.

Failing to replace a clogged or dirty air filter will minimize the airflow to the engine and will reduce your vehicle’s fuel-efficiency. Air filters are inexpensive items, especially on Start My Car, so don’t hesitate to replace it when needed.


3. Drive belt

With a few exceptions, the alternator, water pump, oil pump, power-steering and A/C compressor are all powered by the drive belt, or a system of belts.

Belts in general are manufactured using a rubber-type specifically made to withstand the biggest temperature gaps possible, but nonetheless, the rubber will end up drying out and will start to crack with time.

When the cracks are big enough, the belt will loosen up and could slip on the pulleys, producing a squealing sound. When it happens, failing to replace it timeously may lead to the belt tearing up and ultimately bringing the car to a halt.

Belts should be inspected at every oil change and replaced as soon as surface glazing or cracks are detected.


4. Cabin filter

Cabin filters, also called pollen filters, are used to clean the air entering the cabin from contaminants like pollen and dust. A clogged cabin filter will greatly reduce the efficiency of your climate control system. Many people ignore changing this relatively inexpensive part as there is no fixed service interval for replacement; it depends on largely on the climate wherein you live, the types of roads you travel onto and the mileage you drive every year.

Most cabin filters are located behind the ‘Cubbyhole’ or glove box and are easy to replace yourself, a simple 5-minute endeavour which will save you a considerable amount of money compared to what the car dealerships charge. It’s a simple as unhooking the glove box, sliding out the old filter and in the new one. You can also Google and YouTube tutorials for your specific vehicle.


Braking system

5. Brake pads and discs

Right after oil changes and routine maintenance work, replacing brake pads and discs is the bread and butter for most mechanics, which is to say, brake replacements are a large percentage of their work.


This is hardly surprising as the brakes are used every time you drive your car, so they will wear down and need replacement frequently. Every time you put your foot on the brake pedal, the brake pads are pressed onto the discs (or brake shoes on the drum for older generation vehicles) and slow down the car. The friction, i.e., the rubbing of both components on each other will lead them to wear out and need to be replaced.


Furthermore, in the case of an emergency brake situation, the disc’s temperature will soar and could cause the disc to warp. Warped disc brakes will make the brake pedal vibrate and shudder and will cause premature wear of the brake pads.


Typically, front brake pads do more work than rear pads and need to be replaced more frequently. Warped discs may be skimmed instead of replaced if the warping is not too severe. To ensure your brakes last as often as possible, make sure to have your brake system inspected yearly or at every scheduled service, whichever comes first.


6. Wheel speed sensors

If that annoying ABS warning light illuminates on your dashboard, the problem is usually related to wheel speed sensors. These sensors are located on the knuckles, pointing towards the speed sensor rings installed on the driveshafts or the wheel bearings.

Because of their location, they are constantly exposed to the outside elements while you drive your car, such as sand or water. It is relatively common to see rust infiltrating the sensors and damaging the inside components, leading to false readings and DTCs being recorded in the PCM.

Using an OBD2 scan tool to read the DTC codes will let you know which sensor is damaged and isn’t sending data to the powertrain module anymore. Refer to your vehicle’s repair manual for the correct specification and replace the wheel speed sensors if the value is out of the normal threshold.


Suspension system

7. Stabilizer links

Suspension components are constantly under stress, even more so due to the shoddy conditions of our roads in South Africa.

They must absorb the shocks coming from all bumps and potholes on the roads. Therefore, it’s only natural that these auto parts need to be replaced more often than others. Stabilizer links are, by far, the most common car parts to fail in the suspension system.

This may or may not be true depending on the car model you drive. Vehicle manufacturers use different link designs, and some are simply more efficient and reliable than others.  However, for the average passenger vehicle out there, links will need replacing every 30,000km to 50 000km or so.


8. Ball joints

Ball joints are used to allow your front wheels to move on the vertical axis. Every time your car hits a crack or a small bump on the road, the ball joints are solicited.

Ball joints are lubricated from the factory and a rubber seal is used to prevent water and dirt to enter. After a while, the seal will dry out, crack and rust will start to accumulate on the bottom of the ball joint, pushing the grease out.

Water will also be able to enter and will wash out the remaining grease, whenever it happens, the ball joint will become loose in the socket and a knocking sound will be heard every time that wheel hits a bump, and a squealing sound could be heard when the steering wheel is turned.

It is worth remembering that failing to replace a loose ball joint could lead to more expensive repairs and even a car crash.


9. Control arm bushings

These bushings are located at the other end of the control arms holding the ball joints. They typically don’t include rotating joints like ball joints do and instead use polyurethane bushings to allow the arms to go up and down. As with any other rubber components, they tend to dry out and crack with time.

In most cases, when a control arm bushing is faulty, you should be able to notice the inside sleeve part sliding out of the bushing. When it happens, a low “thump” or metal noise will be heard when driving over potholes.

While I have been told that these bushing have become better designed and more reliable in recent years, if your vehicle is five years or older, the chances are you will need to replace these bushings. Even the best rubber compounds do not last beyond 7 or so years.


10. Shock Absorbers

Shocks absorbers, also called suspension struts, are a little bit different. Unlike other suspension components mentioned before, they rarely need to be replaced because of water causing rust and creating a play inside of it. Instead, struts usually need to be replaced because they are leaking.

The oil contained inside shock absorbers is used to absorb the unevenness of the road. When the seals dry out, the oil will start to leak around the shock’s rod and the oil level will gradually lower until the strut has no dampening effect anymore. Once the fluid level inside the shock reaches a certain level, you should easily notice how the car starts to bounce an excessive amount of time after each bump on the road.

Most fitment centres will test your shocks for free, and it is worth making use of this service at least once a year, or immediately if you feel that the suspension or steering is compromised. Should you need to replace a shock, Start My Car has the full range of KYB shock absorbers online.


Steering system

11. Inner tie rods and tie rod ends

Tie rods and tie rod ends do the same job as ball joints do, if only that they allow the wheel to move horizontally instead of vertically. They are built following the same basic principle and thus are subject to the same defects. Rust will usually be able to enter between the ball and its housing and will cause a play in the wheel.

A mechanic can easily inspect your vehicle and let you know if the tie-rod is the culprit.


Ignition system

12. Spark plugs

On all internal combustion engines, it’s the spark plugs’ job to ignite the air/fuel mixture to create an explosion and ultimately make the car move forward. Spark plugs must withstand an enormous amount of pressure every time an explosion happens.

As time passes, the centre electrode will wear out and misfires could occur. Excessive heat can also cause the insulator to crack, and the faulty spark plugs will end up being short-to-ground and won’t spark anymore. When it occurs, there’s nothing else to do than to replace the plugs altogether.

Most manufacturers regard spark plugs as a regular service part and recommend replacing them at every service (+-15 000km) or every alternate service (+- 30 000 km), and you should follow your manufacturer’s guidelines.

The truth is different types of spark plugs will need to be replaced at different intervals.  The basic copper plugs may last at the very most 50,000km, while Iridium plugs can exceed 100 000km.

Choosing the right ones for your vehicle depends on how complicated replacing the spark plugs is. If you have a V6 engine and putting new plugs in requires the disassembly of the intake manifold, for instance, installing Iridium spark plugs might be a good idea.


Engine Management system

13. O2 sensors

O2 sensors are used to adjust the air/fuel mixture entering the engine. They are installed at different locations on the exhaust system and monitor the amount of unburnt fuel in the exhaust fumes in real-time. Once again, components subject to higher temperatures and excessive pressure tend to fail the most often.

On most vehicles, an O2 sensor is installed right on the exhaust manifold and another one right after the second catalytic converter. Of course, these are the hottest parts of the exhaust system.

Such a high temperature over a long period will inevitably damage the internal components of the O2 sensors and they will need to be replaced. Failing to do so will lead to an incorrect air/fuel ratio greatly reducing the fuel efficiency of your vehicle. Driving with a bad O2 sensor could also cause collateral damage to other expensive components such as the catalytic converter and the emission control system.


Charging system

14. Battery

Another frequently replaced automotive part depending on where you live is the battery. Cold is the number one enemy of car batteries simply because the chemical reaction inside of them proceeds more slowly in cold weather. Sub-zero temperatures will even slowly drain the power contained inside the battery and will also put a strain on the inside components like the cathode plates.

After a while, as the plates degrade, the battery won’t be able to hold enough power to allow the car to start. Such a situation will be exacerbated during the winter season as starting the car also requires more power than usual.

A typical battery will last 4 to 5 years when used in optimal weather conditions but will quickly weaken after 3 years. Batteries should be replaced at the first sign of weakness.


15. Alternator

As another main component of the charging system, the alternator also suffers from big temperatures changes and is co-dependant of your car battery’s health. As your battery ages, the alternator will produce more power to make up for the battery’s lack of efficiency and that often leads to premature malfunctions.

The alternator is driven by the belt and turns roughly 4 to 5 times faster than the engine. This means that when the engine turns 3,000rpm, the alternator pulley is turning at around 12,000-15,000rpm. It’s not hard to understand then why the flimsy alternator bearing may wear out and start producing noise at some point.

It’s important to mention that, just as the battery’s health has an impact on the alternator’s lifespan, the reverse is also true. A faulty alternator will drain the battery and will affect its expected lifespan. To ensure both components last as long as possible, make sure to test your alternator at least once a year, preferably right before the winter season.