How to inspect a used car - illustrated guide

Updated: January 22, 2020

The used car market is full of great choices. All used cars have some flaws or problems; some are minor, while others should be avoided.

Oil condition on the dipstick

The oil condition on the dipstick can tell a lot.

Minor flaws are the ones that don't affect the safety or reliability of the car and can be corrected. Examples include worn tires, minor suspension and brakes problems, scratches, dents, etc. Marking all minor flaws can help you in negotiating the deal. You can request the dealer to repair the issue or to lower the price accordingly.

A used car should be avoided if you spot signs of a major problem.

Signs of flood damage in a car

This car has been flooded.

Major problems include serious rust damage, frame damage (in a truck), engine or transmission problems, smoke from the exhaust, electrical problems, previous accidents, flood damage, lack of maintenance or anything that makes the vehicle unsafe or might require expensive repairs. We wrote this guide to help you recognize signs of potential problems and make a more informed decision.

What you may need when checking a used car

It's a good idea to enlist a friend to help you inspect the car, consider pros and cons and make a sound decision.

Rust

Repaired rust damage.

A small magnet might be useful in detecting repaired rust spots. You might also need a paper towel to check the engine oil and a USB cable or a CD to check the audio system. If you are using a child seat, it's a good idea to take it with you to see if it fits. Researching reliability and common complaints for the make, model and year will help you know about problems to expect in the future, as well as what to watch out for when checking the car.

First step: check for signs of accident repairs and rust

Painted door
This door has been repainted and the color doesn't match.

Take a look at the car from a distance to spot the difference in color between different panels. The front door of the car in the photo has been repainted. It might have been minor damage, but it doesn't look like a high-quality repair.
Mark down any defects you find: cracks on the windshield, dents, damaged lenses, scratched rims, etc.

Check the exterior lines and reflection

Check exterior lines and reflection
Look at the exterior lines. The car on the right has some waviness after a collision repair.

Look along the side of the vehicle. Do the exterior lines appear straight? Look at the reflection, you might be able to see the difference in paint texture or "waviness", which might be the evidence of previous body repairs. Check if all the doors open and close smoothly. Does the driver's door sag or has free play in the hinges when it's open? Do all the body panels appear lined up? Look closely and compare the texture of the paint on different panels. To help you, we wrote a separate article on this subject and included many more photo examples: How to spot signs of accident repair, rust or paint job when checking a used car.

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Check the windshield

Chip in the windshield
The cracks from this chip might spread later

Check the windshield and note any chips, scratches or other damage. Scratches will produce glare when driving at night. Some chips and star cracks, if large enough, can cause the vehicle to fail a safety inspection. Replacing a windshield costs from $320 with an aftermarket windshield to over $1,000 using an OEM part.

Check the sensors in the windshield

Camera in the windshield
This car has a front-sensing camera and a rain sensor attached to the windshield.

Cars with advanced safety features, such as Lane Departure Warning or Front Collision warning, might have sensors attached to the windshield. If the windshield is replaced, some of the sensors (e.g. forward-sensing camera) might need to be re-calibrated. Watch out for signs of tampering (glue, broken covers, scratches) around the sensors; it may indicate that the windshield has been replaced. If it was not done properly, the car may have problems with the safety systems relying on these sensors.

Check the rims

Bent alloy rim
Some aftermarket low-profile rims bent easily.

Some alloy rims, like the one in this photo, bend easily after hitting a pothole. The bent spot could be on the inside. The only way to catch this is during a pre-purchase inspection when the car is lifted on the hoist. A bent rim may cause a vibration on the highway. Replacing a rim like this could be expensive.

Check the manufacturing date of the tires

Tire manufacturing date
This tire was manufactured in the 19th week (May) of 2013.

Each tire has a DOT number or code. The last 4 digits of the DOT code show the manufacturing date of the tire. If the tire is very old (more than 6-7 years old), even if the tread is in good shape, it might need to be replaced, as the tire rubber material degrades over time.

Check tire tread wear

New vs. worn-out tire
New versus worn-out tire

Do tires look worn out? Do they have cracks, cuts, bubbles or other damage in the sidewall? Tires with sidewall damage must be replaced. Watch out for uneven wear; it might be a sign of problems with the suspension or wheel alignment.

The tire in the top image is almost new. The new tires have a tread depth from 10/32" to 11/32" and can last for up to 40,000 miles. The tire in the lower photo might still pass the safety inspection, but is worn out to about 4/32", which means this car will need new tires soon. Look at the wear indicator bar. A set of tires, depending on the size and brand costs from $400 to $1400 to replace. Low-profile 18" and larger tires are more expensive. Run-flat tires cost a lot too. You can look up prices at TireRack.com.

Are all the tires of the same brand? If the vehicle has expensive premium tires (e.g. Michelin), it's a sign that the previous owner didn't mind spending money to keep the vehicle in top shape. Does the tire size match the size specified in the tire sticker?

Visual inspection under the hood

Leaking coolant from the radiator
Coolant leaking from a crack in the radiator.

Before checking under the hood, make sure the engine is OFF, the transmission is in Park and the parking brake is applied.
Watch out for:
• Leaks (avoid the car if you notice major leaks).
• A burnt oil or antifreeze smell (avoid the car).
• Anything that suggests that the car has not been regularly maintained.
• Signs of sloppy repairs (avoid the car).
• Mods suggesting the car has been raced or otherwise abused
If the engine bay looks clean, it doesn't mean that there are no leaks or other problems. Dealers often shampoo the engine before putting the car up for sale. Watch out for leaks underneath the car. Read more: Signs of engine problems when buying a used car.

How does the battery look?

Corroded car battery terminals in a used car
The battery in the left photo looks corroded. The right photo shows the battery that has been recently serviced.

The condition of the battery is one of the indicators of the level of maintenance the car received. Do the battery terminals look corroded or recently serviced? If the battery looks old, it will need to be changed soon. The car battery typically lasts 5-7 years. Smaller-size batteries last 3-4 years. You can request to check the battery capacity (Cold Cranking Amps) during the pre-purchase inspection.

Check engine oil level and condition

Oil condition on the dipstick
The oil condition on the dipstick can tell a lot.

If you are not comfortable doing these tests, leave them for the mechanic. Make sure the engine is turned OFF and the parking brake is applied. Check the vehicle's owners manual for directions. Find the engine oil dipstick. Usually it has a bright handle that says" Engine Oil." Pull the dipstick out and check the oil level and condition. If the oil looks very dirty and the oil level is low, it means that either the engine consumes oil or has been poorly maintained. Check the condition of the dipstick itself; if it's covered with black deposits, like the one with no oil in the photo, it's also a sign of an engine in bad shape. If there is no or very low oil on the dipstick, or coolant mixed with oil, avoid the car. Read more: Signs of engine problems when buying a used car.

Check transmission fluid

Transmission fluid on the dipstick
In this car, transmission fluid looks a bit dark, but still clean. The level is OK

If the car has a transmission fluid dipstick (many modern cars don't have one), check the transmission fluid condition. To see better, drop some fluid on a white paper towel. Transmission fluid should be clean and transparent. If the transmission fluid looks very dirty, or has a burnt smell, it is a sign of excessive transmission wear. See: How to check transmission fluid.

Watch out for signs of sloppy repairs, altered wiring

Poor quality repair
Watch out for sloppy repair job

If something looks out of place or missing, suspect a sloppy repair job. The bolt in the photo clearly looks out of place. There was supposed to be an engine mount in this place, but it's missing. This doesn't look like a high-quality repair. See two more examples of shoddy repairs: sloppy wiring job, bad valve cover leak repair.

Check the VIN number and the manufacturing date

Production date on the VIN sticker
The car is a 2007 model, but it was built in December 2006.

Take a photo of or write down the VIN number. You can find the VIN number in the lower left portion of the windshield or on the manufacturer's sticker. See where the VIN sticker is located. You will need the VIN number to check vehicle history records or if there are any unrepaired recalls. Make sure the VIN number on the papers matches the one in the car. Watch out for signs of tampering. Check the production date on the VIN sticker. When choosing between two cars of the same model year, one that is built at a later date is a better choice, all else being equal.

Inside the car:

Common expensive problems to watch out for:
Infotainment system: freezing, rebooting, lack of response in some areas of the touchscreen.
Instrument panel: warning lights stay on after the engine is started, some gauges are not working properly (e.g. the fuel gauge fluctuates).
Seats: heated seat function or some power functions are not working, the seat jams, not moving all the way, the seat base (frame) is loose/broken.
Sunroof, power tailgate: not opening/closing fully, jamming.
Heating/Air conditioning: No A/C, the A/C for rear passengers doesn't work, lack of heat from the vents.

Do the steering wheel, driver's seat and the inner door handle look worn out? Does it smell bad inside the car? Bad interior odors are difficult to get rid of. Check the condition of the seats.

Worn driver's seat in a used car
The driver's seat looks excessively worn

Look for wear, burn marks and other damage. Minor damage can be repaired; ask if the dealer can arrange for repairs. Check if both front seats slide and recline. Check the condition of the seat belts. Do you feel comfortable in the driver's seat? Can you find a comfortable position using the steering adjustments?

Test power windows, power locks and mirrors. Sometimes a window goes down well, but goes up very slowly or crooked. Loud abnormal noises when a power window is operated indicate a problem.
Test the front and rear wipers and washer functions.
Take some time and test the infotainment system functions. Try pairing up your phone if that's important to you. See if the rear-view camera provides a clear image.
Test the heater and air conditioner. With the engine running, turn the A/C on.

Oil change sticker
An oil change sticker may shed some light on the maintenance history.

You should feel cold air coming from the vents soon after the A/C is turned on. Normally when you turn the A/C on, you might notice that the engine tone changes; it's because the A/C compressor engages.
Watch out for musty smells from the vents.
A burnt oil smell from the vents indicates possible oil leaks in the engine compartment. An antifreeze (coolant) smell is a sign of a coolant leaks. Leaks are signs of problems, it's best to avoid a car.
If the vehicle has a separate HVAC system for rear-seat passengers, test it too. Test all the blower motor (fan) speed settings. Does the heater provide good heat? Avoid the car if the heater works well while driving, but the air from the vents becomes cool when the car is stopped with the engine running at idle. It's a sign that there are air pockets in the cooling system and this could potentially be an indication of engine problems. If there is an oil sticker, check what it says; it may provide some info on previous maintenance. Read also: Signs that a used car was a rental.

Watch out for signs of flood damage

Signs of flood damage in a car
This car has been flooded. You can see the water level mark in the speaker cover. Photo 2.

Flash floods are becoming more common. If a car has been flooded, it's more likely to develop many problems in the future. Modern cars have many electronic components that can get damaged if submerged under water.

The car in the photo has been flooded. You can still see the dirty water level mark in the speaker cover; see photo 2. Look for signs of moisture under the carpet. Check the trunk and the spare tire well for signs of water damage. The history report can also reveal flood damage. Be suspicious if the history report indicates that the car came from an area that recently experienced flooding.

Does the car have a second key, owner's manual, spare tire kit?

Spare tire emergency kit
Check if the wheel lock key and the tools to change a tire are present.

A new car comes with at least two keys or key fobs; ask if the second key (fob) is available and test if both are working. If there is only one key, and it's lost, the car would have to be towed to the dealer to cut and program a new key (fob). This will be expensive.

Check if the car has a good spare tire and a working jack. If the wheels have wheel locks installed, make sure there is a wheel lock key.

If the spare tire is secured underneath, does the lowering mechanism work?

Truck spare tire
This truck has a spare tire secured underneath.

In many trucks, SUVs and minivans, a spare tire is secured under the vehicle. The mechanism that lowers the tire often gets rusted, making the spare tire useless in case of a flat. This is another item that should be inspected in a repair shop on the lift.

Test drive

There are many problems that you can find during a test drive. Test drive for as long as possible to be able to assess the driving characteristics of a vehicle. It's not uncommon for used car buyers to request a second test drive before signing a contract. We wrote a separate post: Signs of problems to watch out for when test driving a used car.

Pre-purchase inspection

We recommend having the vehicle properly inspected by a knowledgeable mechanic before purchase. There are many components that can only be inspected when the car is lifted on the hoist. An important question for any used car in the Rust Belt and Canada is how bad is the rust damage underneath and has the vehicle been rustproofed?
How to get the vehicle inspected in a shop? Many used car buyers arrange to have a pre-purchase inspection done by a local mechanic or new car dealer specializing in that brand. It may cost from $75 to $150. If possible, speak directly to the technician doing the inspection for the explanation of any findings and for general opinion on the car. You might also be able to find a used car inspector who can inspect the car on the spot.

Before signing the contract

Discuss any issues that need to be addressed before signing the contract. For example, if there are scratches or other minor damage, discuss if the dealer can repair it or reduce the price. If the car needs new tires, discuss in detail what kind of tires will be installed: cheap ones or from a reputable brand? If there is only one key, will the dealer provide the second key? It's best to do this in writing; verbal promises are just that, verbal promises. The same goes for warranty, check the contract and see what is covered.