5 Things You Must Check When Buying a Used Car

Buying a used car can be exciting and overwhelming at the same time. Too often, used cars are often sold with hidden damages or problems. To help you avoid buying a lemon, follow our checklist of Things You Should Check When Buying a Used Car.

Read Codes

read codes before buying a used car

Read Codes. Read Codes. Read Codes. Never buy a car without reading the codes.

Get an OBD-II scanner and read the codes via the diagnostic port under the dashboard. A basic scanner can tell you a lot about the engine. If the check engine light is on, you will have the code you can research on your phone.

A pending fault code may be present even if the check light is not on. Basic scanners cannot read airbag, SRS, ABS, and transmission codes. You will have to invest around $150 to get a scanner that can read those systems.

Drive For At Least 30 Minutes

Test Driving  a Used Car

Never buy a car without a test drive. Transmission and engine problems may not be noticeable until the vehicle warms up.

If you buy the car from a private owner, ask if it is OK to take the car for a test drive. Drive at slow speed and higher speeds for at least 30 minutes.

A car could have issues at high speed, such as not shifting properly or feel unstable over 50 mph, for example. Drive around a neighborhood with lots of stops and go. Keep an eye on the temperature gauge during the test drive and the oil light. When you turn on the ignition, the oil light should only come on for a few seconds.

The temperature gauge should never go over the halfway mark. Check out the electronics and the operation of the air conditioner. If it is winter, you should still turn on the AC and see if it is working properly and if the compressor is engaging. Do not drive with the radio on during your test drive, but listen carefully for engine and suspension noises.

Check Airbags / Body / Frame / Interior

buying a used car, deployed airbags

The physical condition of the car is a key factor. You should note any damage and negotiate the price accordingly. If a car has been in a minor accident, it’s not a major concern as long as the seller is honest and telling you what happened. Don’t buy a car with deployed airbags unless you know what you are doing.

If you find damage and the seller tries to hide it, you should be concerned with the purchase. Check the frame under the hood and also in the rear by the spare tire.

You will often notice repairs done here if the car was involved in a serious accident. Look under the car for rust and avoid cars that show an excessive amount of rust.

Check fluids

Check Fluids

Open the hood and check the fluid levels. Note where the car was parked. Park the car in a clean area and let it run for at least a couple of minutes. Now move the car forward or backward one full car length. Look where the car was parked.

Do you see any wet spots underneath?

If you see any black spots, this could be engine oil. If you notice any green fluid on the floor, the anti-freeze is leaking, typically accompanied by a strong smell. In some cases, you may also notice pink fluid, usually the transmission.

Get a Pre-sale Inspection

car inspection at mechanic

Less than 10% of used car buyers do an inspection at a certified mechanic before purchase. Many used car buyers visit the mechanic shortly after buying their cars. Most sellers will allow you to take the vehicle to a mechanic of your choice near their residence.

Find a couple of auto repair shops near the seller and call them. Tell them that you are interested in buying a used car and would like to do a pre-sale inspection.

Ask how much it costs as you will be responsible for paying the bill. Having a car inspected by a professional is worth the cost.

No matter how carefully you look, a mechanic who works on cars all day can quickly discover hidden problems. You want to avoid getting a car that will have major problems with the engine or the transmission. Ask the mechanic for their opinion if you should buy the car or not.

Check History Report

Even a VIN History Report may not show all the problems, but it always a good idea to run a report. A Vehicle history report will show if there are any title problems or if they have been any reported accidents.

It will show if the car has been flooded and reported to the insurance company. It will show if the car has been reported with frame damage. In some cases, you may even see maintenance records on the vehicle history report, but not always.

If you spend thousands of dollars on a used car, you should always spend a few dollars on a history report. There are services like Carfax and Autocheck, but now other companies offer vehicle history reports, which not many people know about.

For example, this VIN Provider provides vehicle history reports at a much lower cost than the two big names mentioned above.


Don’t rush to buy a car because someone else is looking at the car while you are. You don’t want to decide based on emotions when buying a car.

It is best to talk to the seller and make arrangements for inspection and negotiation on a price. Then sleep on it for a night. This will give you time to make a clear decision on your next purchase.

Always Research Common Problems

Every car makes, and model has problems that may be specific to that model. Do some search online for the car you are interested in. See if there are any major problems that other owners have experienced.

When buying a used car, check forums and feel free to ask the community what they think of a particular model. Every car will have some issues, so don’t expect to find a perfect car. You want to avoid models that have major problems, especially related to the engine and transmission.

Check the specific engine that you are looking to buy. One car model car comes in two or more engine sizes. For example, a VW Jetta could have a 1.8T or a 2.5-liter engine. The 1.8T may have some major issues, while the 2.5 liters may be the bulletproof engine you want to buy.

Buying a Used Car From a Dealer

If you buy a car from a dealer, they will often give you a 30-day warranty. In some states, this is even required. If not, they may sell a third-party warranty.

You can also ask a private seller to guarantee if a major problem arises in the first 30 days of ownership. For example, write up a contract covering any major defect over $500 that may come up in the first 30 days or 7 days of ownership. This is a good way to ensure that you will not have any major problems as soon as you purchase the car. A seller who knows their car and is honest will not have a problem with this.

Get this in writing on a bill of sale. This may sound crazy, but it is the best way to protect yourself when you buy a used car.

We hope you find the 5 Things You Must Check When Buying a Used Car guide helpful. Check these troubleshooting and repair guides for more help on your vehicle.


  • Rushit Hila • ASE Certified

    Rushit Hila, an ASE-certified engineer (G1 Automotive Maintenance and Repair), brings over two decades of hands-on experience in the automotive world to his writing. With a strong educational background, including a Master of Science in Engineering and a Bachelor of Science in Engineering, he has honed his skills and expertise through years of practical work. As a respected authority in the field, Mr. Hila is dedicated to offering insightful and valuable content that resonates with both vehicle owners and mechanics.

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