10 tips on how to spot signs of problems when test driving a used car

Updated: March 15, 2020
A pre-owned vehicle is a popular option for car buyers: it's less expensive, you don't have to wait for the delivery and you see exactly what you are paying for. Of course, with a used car, you have to be careful, as it might have some hidden problems.
Test driving a used carYou can catch some engine and transmission problems during a test drive.
A used car history report may help you avoid cars that have been restored after an accident or not serviced regularly, but it won't tell you anything about the current mechanical condition of the vehicle.

This is why a test drive is an important part of the used car buying process. During a test drive, you can catch some signs of problems with the two most expensive to repair components: the engine and transmission. Sometimes, you know that the car should be avoided right after starting it. We know how to test drive a used car, so we want to share a few tips with you.

1. Are you going to be comfortable driving this car?

Mazda RX-8 interior This Mazda RX-8 has tight sporty seats, but not everyone will find them comfortable.
Make sure the car is comfortable and adequate for your daily driving needs. If something doesn't feel right, ask yourself: can I get used to this or will it bother me for as long as I have this car? For example, things like the placement of the controls or design of the gauges are easy to get used to. On the other hand, if the driver's seat is too short or the pedals are too high or you don't have enough legroom or headroom, these issues might be hard to live with, and it's best to find another car. One of our friends had to sell his almost new car, because the pedal placement caused pain in his foot.

2. Is this car ready for a test drive?

Find out about insurance coverage for the test drive. Call your insurance if you are not sure. A used car sold at a dealership could be covered by the dealership's insurance policy, but a car sold by a private owner might not even be insured. Make sure there is insurance coverage before the test drive. To avoid distractions during the test drive, take some time to adjust the steering, driver's seat and mirrors and get familiar with controls and instruments.

3. How the engine starts when it's cold can tell a lot

Blue smoke from a car exhaust If you see a blue smoke from the exhaust, avoid the car.
Many problems are easier to detect when the car is started cold. If the engine has loose pistons, sticky lifters, cracked exhaust manifold or stretched timing chain, you will hear it better when it's started cold. Once the engine warms up, many such problems might not be noticeable.

Avoid the car if the engine makes loud noises when started. Whether started cold or hot, the engine should fire up right away, and run smoothly without stumbling, misfiring or excessive noises. A blue or grey smoke with the smell of burning oil is a sure sign that the car should be avoided.

If the car battery or the starter motor are weak, it's also easier to detect at a cold start too: the engine might crank slower or the car might even need to be boosted to start. Another issue you can catch when the vehicle is cold is the automatic transmission problems. Avoid the car if the transmission engages with a delay when it's cold, even if it gets better once warmed up. All warning lights on the instrument panel should also turn off once the engine is started.

4. Do the heater and air conditioner work?

Testing the A/CWhen you turn the A/C, the air from the vents should turn cold in less than a minute.
We were looking at the used Dodge Dart at a local new car dealership. After the engine ran for a few minutes, we tested the air conditioner, but it didn't work. The A/C light came on, but the air from the vents remained barely cool. A salesperson told us not to worry and that they will recharge the A/C before we take delivery.
If the A/C doesn't work, there is a problem. How do you know if they will actually fix the leak or just recharge it so the A/C will work for a few days? When you turn the A/C, the air from the vents should turn cold in less than a minute. You should also see the engine tone change. This is because the A/C compressor kicks in. If there is not enough refrigerant in the A/C system, the A/C compressor won't kick in.

Check if the heater works well. One of the common problems is when you have a good heat from the vents when driving, but the air becomes barely warm when the car is stopped with the engine running. This could be caused by a variety of problems, some of which could be expensive to repair. Normally, once the car is warmed up, the air from the vents should always be warm when the heater is on and the engine is running.

5. Watch out for signs of automatic transmission problems

Automatic transmission When test driving a car with an automatic transmission, watch out for delays, slipping, harsh shifting or any other signs of a worn transmission.
When test driving a car with an automatic transmission, watch out for delays, slipping, harsh shifting or any other signs of a worn transmission. If you accelerate slowly, you should be able to feel how the transmission shifts gears, unless it's a continuously variable transmission or CVT that changes the gear ratio gradually. The acceleration should be smooth. For example, some cars with a CVT exhibit what they call "judder" when accelerating. You'd feel it as some jerkiness when accelerating, like if the car is hesitating at times. Some double-clutch transmissions are also known for shuddering and hesitation when taking off.

Watch out for a jolt when coming to a stop; some Ford and Chrysler vehicles have transmission problems with this type of symptom. A strong clunk or jolt, when the transmission is shifted into reverse, is also a sign to avoid the car.

Another common problem is when the transmission slips into neutral at times. For example, when you are coasting in Drive and then accelerating, there is a delay, like the transmission is still in neutral, and then it tries to catch up. In some transmissions a worn-out bearing or gear can cause a whining, humming or whirring noise that can be noticeable on acceleration or deceleration.

Also watch out for "gear hunting." It's when you drive steadily, and the rpms keep going up and down, like the transmission doesn't know which gear to shift to.

Transmission repairs are expensive; you would be well advised to pass on the car if you feel that something isn't right with the transmission, even if the dealer tells you that "it's normal for this car" or that they will "update the software." There are plenty of used cars that don't have any of these issues.

6. How to test drive a stick shift

Stick shift Manual transmission.
For cars with a manual transmission, try accelerating and decelerating in every gear and listen for gear noises. A good transmission is quiet. Humming or whining noises is an indication of wear. Shifting in and out of any gear should be easy. Gears should engage smoothly, without much effort or grinding. Another common issue is when the shifter pops out of gear by itself while driving. When releasing the clutch pedal, feel when the clutch starts to engage. If it engages at the very end of the pedal travel as you are releasing it, the clutch might be worn. You can also detect the clutch slipping when accelerating in 3-rd or 4-th gear while driving uphill. If the clutch is slipping, you will see the engine rpms go up without the increase in speed. Replacing the clutch is costly: $900 to $2,200.

7. Abnormal noises and vibrations are signs of problems

This is how a bad wheel bearing sounds.
Many car problems result in abnormal noises while driving. For example, a bad wheel bearing or a transmission bearing can cause a humming noise that gets louder with speed. Watch the video. Cupped tires produce a similar humming or rumbling noise. Bad CV axles will cause clicking noises coming from the front wheels when accelerating in turns. A loud whining noise coming from the engine compartment might be a sign of problems with the power steering pump.
A vibration felt inside when driving can be caused by many reasons, including a bad tire, bent rims, drivetrain problem or other issues. Basically, if there is an abnormal noise or vibration, it's a sign of some problem. If in doubt, test drive another car of the same make and model to compare.

8. Is the vehicle holding the road well?

Steering wheel is off center when driving straight The steering wheel is off center when driving straight. This car needs the wheel alignment checked.
When driving on a straight, flat road, see if the steering wheel is centered and if the car doesn't pull to one side or another. If the steering is off-center when driving straight, there is a problem with the wheel alignment. Some problems with the suspension or wheel alignment can cause the vehicle to feel unstable or 'wander' side to side. If the front tires squeal when doing a slow-speed U-turn, it's also a sign that either the wheels are out of alignment, or there is some problem in the front end. A car with good suspension and properly aligned tires feels very stable on a highway and doesn't 'shift' sideways on bumps or bad patches of road.

9. How do the brakes feel?

Steering wheel shakes while braking Rusted or warped brake discs (rotors) can cause the steering wheel to shake during braking.
Do brakes work well? Watch out for a pull or vibration felt in the steering when braking. The steering vibration (shake) that is only present while braking is usually caused by warped or rusted brake discs (rotors). This problem is often more noticeable when exiting the highway, read more in this article. It's not a very expensive problem, but it should be repaired before you pick up the car.
If the steering wheel pulls to one side during braking, there is a more serious problem with the braking system. The brake pedal that is spongy or goes too far down is another sign of a problem with brakes. Of course, the only way to check if the brakes are safe is to have the car inspected by a mechanic, read more below.

10. Watch out for noises when driving slowly on a rough road

driving on a rough roadWatch out for suspension and steering noises while driving slowly on a rough road.
To catch worn out suspension parts, find some rough road that is safe and drive slowly. It's easier to hear the noises with the windows closed. A rattling, knocking or creaking noise coming from the front or rear suspension indicates a problem that must be checked by a mechanic. If the car shakes and bounces when driving over bumps, the struts and shock absorbers could be bad. Watch out for any rattling or knocking noise coming from the steering. This type of noise is more noticeable when driving over small potholes or unpaved roads. Some of the steering problems could be expensive to fix and must be checked by a mechanic.

Take a used car for an inspection to an independent mechanic

If you like the car, arrange for it to be inspected by an independent mechanic before buying. It's even better if the mechanic is specializing in that brand of car. Don't rely on a written inspection report; try speaking directly to the mechanic. Ask the mechanic, would he or she buy this car and if not, why? Check CarComplaints.com and NHTSA complaints for the most common complaints for this make and model and ask the mechanic about them. Inquire what kind of repairs to expect in the future.
We hope this helps, good luck with your "new" used car!