Motor Expo 2026

After looking for various car brands and models, what's indispensable is going around to inspect used cars at car buying and selling markets, or what's known as car dealerships. However,in this era of borderless communication, we don't need to tire ourselves out by driving around to look. Just search on Google, and many used car marketplaces are easily comparable at our fingertips! Once you find a suitable source, you'll need to arrange to see the actual vehicle. There aresimple steps as follows:

●​ Exterior Condition
For the overall exterior condition of the car, buyers must check the shape and body for any distortion. A car in good condition must have a beautiful shape, with the front and rear bumpers fitting perfectly with the car's body. The hood must open and close easily and securely. The edges of the hood, both left and right, must be parallel to the fender edges. All car doors, the door edges must align properly with the pillars. For adjacent doors, the door edges must not be crooked or overlapping. The tailgate must also close securely, aligning with the left/right fenders and the rear bumper.

● Lighting System
Headlights, turn signals, and taillights must be in their original condition. The color of the lights should not differ. If the lights have been used, they should not look suspiciously brand new. Open the hood to check for factory weld marks. The nameplate indicating the engine number and chassis number must match the registration book. All windows will have a factory stamp and production code. If the car has replacement windows, you will know immediately because the stamps and symbols will not be the same.

● Car Color
If you want a car in good condition, the car's color might not be exactly what you desire. If you don't find the perfect color, you'll have to consider your second favorite.When evaluating the car's paint condition, it is crucial to ask to see the registration book. Ideally, the car's color should be original, with no reported changes. If a change is reported, there must be a clear explanation.

In addition, the paint condition must be checked. Most used cars at dealerships receive a full repaint, or what's called “a bath.” When the paint is fresh, it might distract buyers from noticing other details. Here, buyers need to rely on sunlight or bright outdoor lighting to be able to see other details around the vehicle. When examining the paint, if you look in bright light, you'll be able to see how well the paint job was done, and the quality of the paint, primer, and lacquer. If it's a newer car, it might not have been repainted yet. Try checking by tapping around the car to listen for differences in sound. If there's a different sound anywhere, you need to check carefully whether that part has been in an accident. Open the front and rear hoods, as well as all four doors, and observe the color difference between the interior and exterior of the car. They should be the same color or tone, without much difference, except for the engine bay, where the color might differ due to prolonged heat exposure.

● Engine Bay, Passenger Compartment, and Rear Luggage Compartment
Engine Bay: It is essential to inspect this thoroughly. You can immediately tell if the car has been in an accident or collision on any side. The front beam of the passenger compartment must be in its original, thin condition, with no new paint or touch-ups. The front beam must be well-formed and beautiful. Factory-stamped weld marks must be genuine, with no additions. Various holes, both round and oval, must be in their original, unmodified state. If round, they must be perfectly round, not distorted. The holes and weld marks on the left and right fenders must be aligned. Inside the engine bay, there must be no signs of welding, cutting, or new paintwork. The inner edge of the hood must be beautifully shaped, with no unsightly additions or paintwork.

Inside the passenger compartment: You must check for cracks or damage to the console and door panels. All four doors and door locks must function normally. If the car has power windows, all four windows must be able to open and close. All control buttons and switches must be functional.
Trunk: Open and lift out the spare tire, and remove both the left and right taillight cover panels completely to check if there has been a rear collision or accident. The car must not have been repainted and must be in its original condition, with all original factory paint.

● Engine
Inspecting the engine is one important matter. Besides checking the engine's condition, you must also start the engine. The engine must start easily and shut off completely, run smoothly, without any misfires. Gaskets and O-rings of the engine must not leak. This might be difficult to check, as dealerships likely clean the engine until it looks brand new.

After running the engine for a while, try revving it to see if there are any unusual symptoms. If there is a loud noise in the engine bay, or if the engine stutters when revved, it indicates an imperfection in the engine. But if the engine runs smoothly, you should check the temperature gauge to see if it's working normally. In most cars, the water temperature gauge should not go above half. Additionally, observe the electric fan while it's operating; the airflow must be strong and not make loud noises. The tip of the exhaust pipe should be smooth in color. If it's a gasoline engine car, there should be no black or white smoke coming out. If the engine is in good condition, and you place your hand near the exhaust pipe, you will feel moisture mixed with the exhaust.

● Air Conditioning System (AC)

You must try turning on the AC switch to check if the compressor is working and if the AC still has good compression and delivers consistent cooling when the engine is at idle. The AC compressor should not make loud noises when operating. Don't forget to check the power steering pump's operation for cars with power steering by trying to turn the steering wheel left and right. The power steering pump must operate quietly. The steering wheel should not feel heavy on one side or light on the other; if it doesn't, it's good.

● Suspension System
Inspecting the suspension system can be a bit tricky; you might need to bend down to see if any parts are damaged. Starting from the front, bend down to check the oil pan and transmission oil pan for dents or leaks. Also, scan around the left and right wishbones to see if they are deformed, dented, or bent. The front beam must not have excessive scratches or dents; if there are marks, they should be from general use. The chassis must be in good condition, and the buyer must bend down to inspect around the car to ensure the chassis has no dents, collapses, cracks, or rust.

As for shock absorbers, for most cars that have been used for many years, the performance of the shock absorbers will have significantly decreased. Some cars even have broken shock absorbers. Therefore, if you haven't had a chance to drive it, try pressing down on the front and rear of the car to make it compress and rebound. After stopping, the car's shocks must rebound quickly and not bounce up and down multiple times.

In addition, checking the steering rack ball joint can also be done by quickly turning the steering wheel left/right when the engine is not running. If there is a rattling sound, it indicates that the steering rack ball joint may be damaged. And all four tires must be in usable condition, without cracking, and should be the same brand and model on all wheels. The tire treads must all be in good condition.

● Registration Book (Vehicle Registration Document)
This is extremely important when choosing a used car, as the registration book correctly shows the car's owner, registration date, engine number, chassis number, car color, and engine displacement. Car buyers must thoroughly check if the information in the registration book matches the actual vehicle. Registration books that have been replaced with a newer version or have been transferred from another province must also be carefully checked.

Additionally, you can find out how many times the car has changed hands. If it's a good car, it shouldn't change owners frequently. The front/back of the registration book will show various reported changes, such as a change in car color or engine replacement. Used car buyers must carefully review this before making a purchase decision every time. 

After you have purchased and correctly transferred the documents through verification, you should set aside a portion of money for various maintenance costs, as follows: 

● Change all fluids!  
Start by taking the car to drain the engine oil and replace the filter, because we don't know how long it's been since the previous owner changed the engine oil. Additionally, both manual and automatic transmission fluids should be changed at the same time. For rear-wheel-drive cars, the differential fluid should also be changed simultaneously. Andpower steering fluid: check if the color of the fluid has changed from clear red to murky black. If the power steering fluid is black, it indicates that the internal power steering system is quite dirty, and you should promptly have it changed at a service center or a specialized power steering repair shop.

Radiator water: Check how much is missing from the reservoir and if there's a lot of algae buildup. If the radiator water is murky with a lot of scale buildup, take the car to a radiator shop to have it flushed and replaced with new coolant, and also check all water hoses, as rubber hoses have a service life. Hoses must not have cracks or tears, and they should not be stiff; they should be pliable when squeezed.
 

● Tires and Brakes
Tires and brakes are very important, and we must pay close attention to them, because poor tires and brakes can easily lead to accidents. All tires on the car, when used normally, must be in usable condition. Many times, car buyers might encounter bulging tires or a vibrating steering wheel when driving. Before buying a car, the tire tread might look perfect, but in actual use, it might not drive well, possibly due to bulging tires or retreaded tires. If you frequently need to travel long distances, it's more reassuring to buy new tires. While you're at it, have the shop perform wheel alignment and balancing at the same time. Don't forget the spare tire; you should check its condition and air pressure to ensure it's in normal usable condition.

As for the brakes on all four wheels, which are responsible for stopping the car, self-inspection is quite difficult because you have to bend down and use a flashlight to look at the brake calipers. If you're unsure, take the car to a service center to have all four brake pads checked thoroughly, including disc brake pads and drum brake pads, and also check the brake discs to see if they need to be resurfaced at the same time.
 

● Belts
Belts are essential. After purchasing a car, the user must check them thoroughly because belts are crucial for the car to run, including other operating equipment. Starting with the engine belt (timing belt), its lifespan is between 70,000-100,000 kilometers. Buyers cannot know if the previous owner has replaced it, which is difficult to guess. If the car has been serviced at a service center, you can check its history there. But if the car has not been serviced at a service center, you must have a mechanic inspect the condition of the belt. If replacing the belt, the car user can note the mileage after changing the belt. Then we can always estimate the actual lifespan of the belt. If changing the belt, it should be changed along with the belt tensioner pulley at the same time. As for the alternator belt, AC compressor belt, and power steering belt, you must check their condition to see if they are nearing the end of their lifespan. Observe the grooves of the belt for any cracks. How thin has the belt become? Is the belt too tight or too loose?

● Suspension System and Drivetrain
The suspension system, also known as the car's undercarriage, if after using the car for a while, you are not satisfied with its performance, such as loud noises when turning, rattling sounds echoing through the steering wheel when driving on rough roads, or shock absorbers being too soft causing uncertainty when cornering, car users should consult a mechanic immediately. This is because every car's suspension system has a lifespan. Those buying used cars will not know how well the previous owner maintained the car or what their driving habits were. Some cars look beautiful with no collisions, but the previous owner drove them roughly, causing the suspension system to degrade and fail quickly. Inspecting the suspension system must be done item by item. For instance, if there's a loud noise when turning, you need to check the drive shaft, steering rack ball joints. Or if there's a loud thud when hitting a pothole, you should check the control arm ball joints, control arm bushings, or anti-roll bar bushings. If the car doesn't grip the road well and sways when driving, try checking the front/rear shock absorbers to see if they have deteriorated. Replacing with new shock absorbers is not expensive these days, and it provides a more comfortable drive than repaired shock absorbers.

It is evident that the used car business is reflecting many issues for us to see. Therefore, if we trade with honesty and fairness, it is commendable. We commend good entrepreneurs who are ready to implement government policies, not for anyone else, but for their own business.

Read related article: Warning! Never use open transfer when buying or selling a car 

Compiled from ● autoinfo.co.th / Story by : Natthawet Yotsaeng ● 4Wheels Magazine  ● Department of Land Transport