Buying a used car can be a good way to save money because it costs less than buying a new one. But it does come with some risks. A lot of used cars have problems that aren’t obvious at first but can cause expensive repairs, safety issues, and long-term headaches.

The first step to avoiding an expensive mistake is to learn about the most common problems in used cars. You can spot warning signs before you buy if you look closely and know what to look for. In this guide, we’ll talk about the most common problems that come up in used cars, how to find them, and what to do if you find them.

Why Used Cars Often Have Problems

On the outside, a used car can look great. It might have low mileage, clean interiors, and shiny paint. But there could be mechanical or structural problems that don’t show up until you drive off the lot.  Most of the time, these problems are caused by normal wear and tear, bad maintenance, or accidents that weren’t reported. In some cases, the sellers might not even know about the problems.

If you don’t notice these issues before you buy, you could end up with:

• Unplanned repair costs
• Lower value when sold again

• Safety risks
• Legal problems if the seller didn’t tell you about big problems
You have an edge if you know what to look for. It helps you buy with confidence and get the best deal for your money.

1. The issues in the engine that could cost you thousands

The engine is the most important part of a car, but it is also one of the most expensive to fix.
Common engine problems in used cars are: 
• Oil leaks that happen a lot around the timing chain cover, oil pan, or valve cover gasket. If you don’t fix a small leak, it can cause long-term damage because low oil levels can make the engine overheat or stop working completely.
• Worn spark plugs, clogged fuel injectors, or problems with the timing could be to blame for poor performance. If the engine is slow, misfires, or has trouble starting, it could mean that there are bigger problems.
• Strange sounds like knocking, tapping, or grinding could mean that the bearings are worn out, the valves are broken, or there are problems with the pistons. These noises usually mean that expensive repairs are coming up. Too much exhaust smoke could mean that oil is burning, coolant is leaking, or there is a problem with the fuel system.

When you see blue smoke, it usually means that oil is getting into the combustion chamber. When you see white smoke, it could mean that the head gasket has blown. A professional mechanic can check for leaks, run a compression test, and look at the timing belt or chain. These checks can keep you from having to buy a car that needs a new engine.

2. Transmission Problems That Make Driving Hard

Transmission repairs are some of the most expensive in the car world, and they can cost thousands of dollars. Sadly, used cars often have problems, especially those that have been driven a lot or haven’t been well cared for.
During a test drive, keep an eye out for these warning signs:

• Gear shifts that are slow or rough
  • Gears that slip, which means the car suddenly speeds up or slows down
  • Noises that sound like grinding when shifting
  • Transmission fluid that smells burnt or looks dark

The gears on an automatic transmission should change smoothly, without any jerks. A manual transmission should engage gears without any problems, like grinding or resistance. Check the service history to see if the transmission fluid has been changed on a regular basis.

3. Brake System Wear That Compromises Safety

When buying a used car, you should never forget about the brakes. They are one of the most important safety features in any vehicle. Even if the car looks and drives well, broken brakes can quickly make a safe drive into a dangerous one. Worn brake pads and damaged rotors are two of the most common problems that mechanics find during a pre-purchase inspection.

These parts wear out over time, especially if the last owner drove aggressively or didn’t take care of regular maintenance. If you hear any strange noises or see that the brakes squeal, grind, or make any other strange sounds when you press the pedal, they need to be fixed right away. If the brake pedal vibrates or pulses, it could mean that the rotors are warped.

If the pedal feels soft or spongy, it could mean that there is air in the brake lines or that the master cylinder is broken. If your car pulls to one side when you brake, it could be because the calipers are stuck, the pads are wearing unevenly, or there is a problem with the hydraulic system.

Brake repairs are usually less expensive than major engine or transmission work, but ignoring them can have serious effects. Bad brakes make it harder to stop and can cause accidents, especially in emergencies or on wet roads. Before you buy, always check the pads, rotors, and brake fluid to make sure they are in good shape. Ask for a separate brake test during your inspection if you can. This will help find problems that aren’t obvious during a short test drive, like ABS problems or brake fluid leaks.

5. Suspension wear that makes it less comfortable and harder to control

A good suspension system makes the ride smooth and the handling stable. Shock absorbers, struts, or bushings that are worn out can make a used car feel bouncy or unstable.
If your car’s suspension is having problems, you might notice:

• It bounces too much after hitting bumps
  • The tires wear unevenly
  • The car pulls to one side while driving
  • There are clunking noises coming from under the car

The cost of suspension repairs can vary, but not getting them done can make you less safe and comfortable. A mechanic can quickly check the steering and suspension systems for damage or wear.

6. Rust and Corrosion That Threaten Structural Integrity

Rust is more than just a problem with appearance. If you don’t fix it, it could damage the car’s frame and make it less safe. In Australia, coastal areas are more likely to have rust problems because of the salty air.
Look for rust in these places:
• Wheel wells and the undercarriage
• Around the doors and trunk
• Near the battery tray and under the hood 
• The exhaust system
You can usually get rid of surface rust, but deep rust in the frame is a big problem. If there is a lot of rust, the car may need expensive repairs or be unsafe to drive.

7. Electrical Problems that can be hard to figure out

Electrical systems are very important to modern cars because they control everything from the lights and windows to the engine. Old, worn-out, or poorly repaired used cars often have electrical problems.
Some common problems are:
• Windows or locks that don’t work right
• Warning lights on the dashboard that won’t turn off • Lights that don’t work inside or outside the car • Sensors that don’t work right that cause performance problems
Fixing electrical problems can take a lot of time and money, especially if the wiring harnesses are broken. It is very important to check all of the electrical functions during your inspection.

8. Tyre Problems That Show Lack of Care

People often forget about the tires when they buy a used car, but the condition of the tires can tell you a lot about how well the car was taken care of.
Look for:

• Tread worn below the legal limit
  • Uneven wear that shows alignment or suspension problems
  • Cracks or bulges in the sidewalls
  • Tires that don’t match on different wheels.

It can be costly to replace all of your tires, and ignoring alignment problems can cause them to wear out faster. If your tires are in bad shape, always set aside money to replace them.

9. Problems with heating and air conditioning

In Australia, where the weather can be very bad, climate control is a must, even though it may seem like a luxury. When you take a quick test drive of a used car, you might not notice that the air conditioning or heating isn’t working right.
Some possible problems are:

• Leaks that let out too much refrigerant
  • Broken compressors or condensers
  • Vents or fans that are blocked
  • Leaks in the heater core that make windows foggy and lose coolant
• Depending on the problem, repairs can cost anywhere from a few hundred dollars to several thousand dollars. Make sure to thoroughly test both the heating and cooling systems.

10. Leaking fluids other than engine oil

Not just the engine can leak in a used car. If you don’t pay attention to these leaks, they could do a lot of damage. Look for leaks in the following fluids:
The fluids should be at the right levels and not have any dirt in them. A mechanic can find the source of leaks in hoses, seals, and gaskets before they get worse.

11. The Check Engine Light’s Alert

A check engine light could mean anything from a loose gas cap to big problems with the engine. Don’t ignore it when you check out a used car. A diagnostic scan can find out exactly what the problem is. Some problems are easy to fix, while others may need a lot of work. Always ask for a report and an explanation of any fault codes that are still active.

12. Infotainment or navigation systems that don’t work

Touchscreens, GPS navigation, and Bluetooth are common features in modern used cars. Software bugs, old maps, or broken touch panels can all cause these systems to stop working. Even though they might not make the car harder to drive, repairs or replacements can cost hundreds or even thousands of dollars.

13. Safety sensors or airbags that don’t work

Over time, airbags and crash sensors can wear out or stop working because of past accidents. A broken airbag system might turn on a warning light, but in some cases, it might just stop working without making a sound. Before you buy, always check the SRS (Supplemental Restraint System).

14. Damage or leaks in the exhaust system

Exhaust leaks can happen because of rust, corrosion, or damage from an impact. A broken exhaust not only makes more noise, but it can also let dangerous fumes into the cabin. Also, damage to the exhaust can cause emissions tests to fail in states or territories where testing is required.

15. components of the fuel system that don’t work right

Problems with fuel pumps, injectors, or filters can make the engine run poorly, stop working, or be hard to start. These problems often happen in used cars when the fuel is dirty or when the car sits for a long time without being driven.

16. Problems with the climate control system

Climate control systems can have more problems than just air conditioning. They can also have broken temperature sensors, blend door actuators, or control modules. This can stop the cabin from getting hot or cold enough, which can make driving uncomfortable all year.

How to Protect Yourself from Common Problems in Used Cars

A full inspection before you buy is the best way to protect yourself from problems you can’t see. To protect your purchase, do the following:

1. Set up a complete inspection before you buy

Get a qualified mechanic to do a full inspection on any used car you want to buy. This means looking at the tires, electronics, engine, transmission, brakes, and suspension. When professionals inspect a car, they often check for fault codes in the onboard diagnostic system (OBD-II), measure the thickness of the brake pads, check the quality of the fluids, and look for leaks. In Australia, companies like RACV, NRMA, and Mobile Vehicle Inspections give you detailed reports with repair estimates that you can use to negotiate or avoid buying something that might be a bad idea.

2. Ask for and read the full vehicle history report

A vehicle history report shows important information like past accidents, repair records, odometer rollbacks, and registration information. You can get this in Australia through the PPSR (Personal Property Securities Register) or through businesses like Car History and REVS Check. Looking over this report can help you find out if the car has been in any major accidents, been damaged by flooding, or had the same mechanical problems over and over again. This information is important to avoid cars that have weak structures or problems that keep coming back.

3. Find out about performance and handling problems by taking test drives.

A full test drive should be more than just a quick trip around the block. Check how well the car accelerates, brakes, steers, and feels comfortable on the suspension by driving it on city streets, highways, and bumpy roads. Listen for strange sounds like knocking, grinding, or whining. These could mean that the engine, brakes, or transmission are having problems. Also, check that the air conditioning, heater, and electronics all work as they should.

4. Talk about repairs or change the price of the item.

You have two main choices if problems are found during the inspection or test drive: ask the seller to fix them before you buy the car, or negotiate a lower price to cover the cost of repairs. To back up your request, get written estimates from a mechanic.

You can use this information to your advantage when you negotiate. For example, if worn brake pads will cost $400 to replace or a leaking radiator will cost $800, you can use this information. This way, you can either get a car that works well mechanically or save enough money to fix it yourself.

5. Keep a schedule for preventive services after you buy the car.

Regular maintenance is important to avoid expensive problems later, even if your used car is in good shape when you buy it. For oil changes, brake checks, tire rotations, and fluid replacements, follow the service intervals that the manufacturer suggests. Look out for early warning signs like dashboard warning lights, changes in fuel economy, or strange noises, and take care of them right away. Preventive care not only makes your car last longer, but it also keeps its resale value high.

Why Research and Maintenance Are Important?

After you buy a used car, you’re not done. Keeping up with regular maintenance is the best way to avoid problems in the future. Always remember to change the oil, add fluids, and get the car serviced on time.
Also, look up problems that are common with the make and model you’re buying. You can get ready for some cars’ known problems ahead of time.

Closing Remarks

If you choose wisely, used cars can be a great deal. You can avoid making expensive mistakes if you know what the most common problems are with used cars and how to find them. You can find a good used car that fits your needs without breaking the bank if you have it professionally inspected, take it for a long test drive, and do your research. People who know what they’re doing leave happy, safe, and sure of their choice.

Read more about top tips to buy used cars in Australia.