The used car market is exploding. So it was to be expected that used car problems would rise, too. That said, buying second hand these days does not need to be an inferior experience. In fact, many older cars can feel almost like new. And they will often safely reach 150,000-200,000 miles without major repairs. Still, when opting for a used car, you will need to factor a little more wear and tear into your budget.

In this overview, we want to inform you about the most common used car problems. This should help you filter out the important issues of a used car from the less important ones. In the end, you will never be able to totally rule out any defects. What you can do, however, is to at least prevent as many nasty surprises as possible.

What to do if things really go wrong?

As of October 2015, legislation for car purchases in the UK has changed. In many respects, it has improved your rights and shifted more responsibility towards dealers.

It does not give you a wild card, however, to ignore potential problems.

Under this new Consumer Rights Act, you are entitled to reject the vehicle you bought within 30 days. This gives you a more than acceptable time frame to discover defects you did not spot when inspecting the car at the dealership. It also gives you time to see how the car behaves in a more realistic day to day driving environment.

Once the 30 days have expired and you detect a defect, you can no longer simply return the car. But you may still be able to get a repair. If you can reasonably assume the problem was there at the time of purchase, you can ask for a free of charge replacement or a repair.

Limits to Your Rights

This sounds great on paper. Be advised though, that there are limits to the Consumer Rights Act, as Citizens Advice have pointed out. The dealer does not need to take responsibility for your used car problems, if

  • you were told about the fault when you bought the car – and someone fully explained what the problem meant
  • you inspected the car and should’ve spotted the problem, for example a dent
  • you’re just unhappy with how much you paid for the car
  • you caused the fault

Clearly, then, the Consumer Rights Act has improved a lot for the better. But it has not relieved you from taking a good look.

What should you look for, exactly?

To avoid costly mistakes, it helps a lot to know which potential problems of a used car arise more often than others. A still fairly recent article by leading car magazine Auto Express lists the ten most common used car problems:

  1. Gearbox
    Together with the electrical system of a car and the clutch, the gearbox is by far the most typical used car problem.
  2. Electrical
    Many cars these days sport an impressive array of appliances: MP3 players, sometimes video systems for backseat passengers, parking assistants, ABS and many more. Although quality has greatly improved, any of these can obviously break down at any time.
  3. Clutch
    This is a vehicle part that won’t typically break down straight away. The older the car, however, the bigger your chances of a clutch issue.
  4. Turbo
    As auto express point out, the turbo charger is not just one of the most common used car issues. It is also one of the priciest. This makes it even more vital to make absolutely sure it is working fine when buying the car.
  5. Brakes
    You use your brakes every single time you drive your car. Few other parts are submitted to so much wear and tear. You can do a lot to offset brake problems by changing your driving style. But you can never rule them out entirely.

What should you look for, exactly? Pt. 2

  1. Alternator
    Alternators will gradually disappear from the market, as electric cars and hybrid models take over. But they can still cause problems in older models.
  2. Cylinder head gasket
    At roughly 3%, this is a surprisingly common issue.
  3. Air-con condenser
    Air conditioning systems used to be restricted to luxury cars. As they have become more affordable and popular – or even, as Auto Express put it, ‘a necessity for those odd hot days’ – repair numbers have risen, too.
  4. EGR valve
    Few drivers even knew the meaning of this abbreviation prior to the recent emissions scandal. This has changed. Today, it is a well known fact that EGR valves are one of the more frequent issues with any car. (and the abbreviation stands for Exhaust gas recirculation, in case you were wondering)
  5. Window motor/regulator
    Not the most vital part of your car, not one of the most expensive repairs. Still, it is troubling that 2.2% of cars will eventually need to have this part repaired over the course of their life span.

Even Older Cars – Even More Problems


The above mentioned used car problems can affect any car you’re interested in. As soon as you start taking really old cars into consideration – meaning, older than ten years and/or with more than 100,000 miles on the odometer – there are some additional potential issues you should be aware of.

Here are the most important of those issues.

The following list was compiled by website fiix:

  • Oxygen Sensor: The Oxygen Sensor is small, but important part of the exhaust control system of your car. It verifies whether there is any uncombusted oxygen in your exhaust. Since this operation is performed constantly, oxygen sensors can break down after many years of use. They are often routinely replaced after about 150,000 miles. But they can be defective earlier than that. Thankfully, they are not extremely expensive to repair.
  • Catalytic Converter Replacements: Catalytic Converters are extremely durable and high-quality devices. In most cases, they should last a car’s entire lifetime. As fiix point out, though, catalytic converters can get damaged if other parts of the exhaust system experience problems. Since they are extremely expensive to replace, it is therefore essential to make sure the car’s exhaust system is in a good shape. (more about that later on)
  • Ignition Coil and Spark Plug: Although quality has improved significantly with these items, it goes without saying that they are still prone to wear and tear. Replacing them does not need to be particularly expensive. But if the problem remains undiscovered, it can cause far more severe damage to other parts of your car.
  • Thermostat Replacement: Similar to the Oxygen Sensor, the thermostat has a regulatory function: It measures the temperature within your car’s engine. Over time, this mechanism can gradually become less effective and eventually wear out.

Older cars are generally harder to assess than fairly new ones.

This is because even minor defects at the time of purchase can quite quickly combine into major problems. This is one of the reasons why it can sometimes pay off to have a mechanic perform a vehicle inspection prior to purchasing a used car.

A Closer Look: Before Buying

Obviously, there are some things you can do yourself to reduce your chances of buying a lemon. Even with an untrained eye, you should be able to detect quite a few of the above mentioned issues.

Here’s how that works:

To test the gearbox and brakes, simply take the car for a test drive. Submit these parts to a diverse set of realistic tests: Drive the car uphill, speed up quickly, take a fast brake etc. This should help you spot any issues quite quickly.

The electrical system may be a little harder to assess in detail. What you can do, however, is to simply turn on all electrical devices and check if they are working properly. This won’t rule out potential issues entirely. But it will at least provide you with useful information on the current status quo.

Start Me Up


Battery and alternator problems typically manifest through long ignition phases. I.e. the car will take a long time to start up. Issues with the exhaust system don’t require a degree in car mechanics either. The colour of the exhaust fumes can indicate what potential issues the car has:

  • Black smoke may indicate that the ratio of air to fuel is skewed towards fuel.
  • Blue Smoke is a sign of oil getting burned.
  • Heavy white smoke is a more worrying indication that there is coolant in the exhaust. This will require an expensive repair.

Fluid leaks are a surprisingly frequent cause for disputes between drivers and dealers. You should definitely take a look underneath the car. But for smaller leaks, assistance from a trained mechanic will be helpful.

Belts and hoses will show physical signs of use, which you should be able to detect simply by opening up the hood and taking a look at them.

Do Your Research

It goes without saying that the more you know, the more you should be able to spot used car issues before they turn into a veritable reason for a repair. Organisations like Consumer Reports have therefore compiled reliability reports. These contain the most important facts about the majority of models currently available on the market. They mostly combine statistical data about the frequency of repairs with hands-on test drive experience. Studying these before setting foot in a dealership will provide you with an excellent overview of which models to prefer over others.

In addition, as soon as you’re in the last stages of the buying process, spend the few Pounds it costs to obtain a car history. Although it is by no means a guarantee you won’t encounter any problems with your used car, it has the advantage that it provides you with concrete information about the car at hand.

Be Realistic

Car website jalopnik has published a humorous and informative article against the frequent shaming of car dealers. You can read it for yourself here. Although we don’t agree with everything here, it does help to understand that a used car will naturally experience more problems than a new one. As long as you inform yourself well and factor that into your buying considerations, you won’t just reduce your chances or expensive repairs – but the risk of ending up disappointed as well.