Buying a used car or truck can be both intimidating and tedious. It is the second largest purchase after mortgaging a home. Almost every used car on the road will have some sort of issues.
Here are the steps I suggest to make sure you do not end up with a faulty used vehicle. I hope it will give you peace of mind.
Written by Greg Smokes
I have been around auto auctions for decades. I have worked at junk yards in Georgia. I have also worked at body shops that bought junk cars at salvage auctions and rebuilt them.
Do not buy it if
- The temperature needle climbs to the high side.
- The engine is making knocking noises.
- The oil on the dipstick looks milky.
- The rpm suddenly jumps during the test drive.
- The seller will not let a mechanic look at it.
Check the Vehicle History First
Purchasing Carfax will let you know the history of the car whether it is clean title or it has been in an accident. For a low investment it will save you a lot of problems down the road.
Carfax is not on the list of approved NMVTIS providers for consumers. I suggest that you also run the VIN via the three tools below.
Probar un vehículo usado
El primer paso es prueba el vehículo. Here is what to pay attention to during the drive.
Listen for abnormal noises
| What you notice | What it usually means |
|---|---|
| A growling noise | Wheel bearing |
| A whining noise | Power steering pump |
| Squeaky noises from the suspension | Strut or bushing |
Check the steering system
| What you notice | What it usually means |
|---|---|
| The steering is difficult to turn | Power steering problem |
| Vehicle steers to one side | Alignment issue |
| Car drifts from right to left and vice versa | Worn steering parts such as the rack and pinion |
| Vehicle suddenly jumps from left to right | Worn out control arm bushing |
Escucha los ruidos del motor
| What you notice | What it usually means |
|---|---|
| Knocking noises | Worn main or rod bearings. It can also be piston slap. |
| Ticking noises | The engine may need a valve adjustment |
| Grinding or rattling from the front of the engine | Worn water pump |
Watch the transmission for slippage
Pay close attention to the transmission for slippage. If the rpm suddenly jumps during a test drive, this is a sign of a slipping transmission.
Watch the temperature gauge
During the test drive, give close attention to the temperature gauge. The temperature needle should be steady right at the center line.
If it suddenly starts to climb to the high side, that means the vehicle is overheating. This can be a sign of:
- A bad water pump
- A stuck closed thermostat
- A clogged radiator
- A faulty radiator cap
- Worst of all, a blown head gasket
At all cost, do not purchase the vehicle when it is overheating or making knocking noises unless you are certain it is a cheap fix.
Check the brake system
With the vehicle off, step on the brake pedal a few times. It should become firm.
If it stays soft or sinks to the floor, the brake system has a problem. It can be a leak or a faulty master cylinder.
Hold the pedal down and start the engine. The pedal should drop slightly. That means the brake booster is working.
Listen for squealing noises coming from the brakes. If it is present, the vehicle needs brake pads or new rotors.
Inspección del vano motor
After the test drive, if the vehicle passes I recommend you to conduct a visual inspection.
Engine oil
First thing is to open the hood and compruebe el aceite del motor y realiza una prueba de olor. El aceite del motor debe estar limpio y no oler a quemado.
Check the engine cap for any milky color. A small amount under the cap can be condensation from short trips. Pull the dipstick next.
If the oil on the dipstick is milky too, that means you likely have a blown head gasket; and at this point, do not purchase the vehicle.
Also, you want to check for any small or fine metal particles that may be present in the engine oil. If metal particles are found, that is a sign of a worn engine.
Transmission fluid
Next, check the transmission fluid. Remove the transmission dipstick. The fluid should usually be bright red.
If the color is dark and dull, that means the transmission fluid has not been changed recently. A burnt smell means the transmission has been running hot.
Many newer vehicles do not have a transmission dipstick.
Coolant
Cuando el motor esté frío, get a used rag and place it on top of the radiator cap and remove it. Do not open the radiator cap on a hot engine.
Check the coolant color. The color depends on the vehicle. Green and pink are common. The coolant should look clean.
If it looks milky, that means you got a blown head gasket or a bad radiator in which the radiator coolant and transmission fluid are mixing.
Check the transmission dipstick for a pink milky-looking substance. If it is present, the radiator is likely bad due to a leak.
Radiator fan
Make sure the radiator fan turns on when the engine reaches operating temperature.
Tires, Body and Scan Tool
Tires
Check the tires for baldness and cracks. Look for punctures from nails and road materials.
Place a penny in the tread with Lincoln’s head upside down. If you can see the top of his head, the tire needs to be replaced.
NHTSA says a tire is not safe when the tread is worn down to 2/32 of an inch.
Body and paint
Check the exterior for possible damage. Look at the hood, bumper and trunk alignment. Look for mismatching paint.
If a panel is misaligned, the vehicle has likely been involved in an accident.
Scan tool
Use a scan tool and scan the vehicle for codes. You also want to check that all the I/M readiness monitors are ready.
If they are not ready, that usually means the battery has been disconnected or the check engine light has been reset.
The monitors only go back to ready after the vehicle has been driven.
Checking a Car at an Auction
Auction vehicles are sold as is. Most auctions will not let you test drive the vehicle. I have run a public car auction myself.
You can still do the engine bay inspection during the preview. You can also check the tires and the body. Bring a scan tool and ask the auction staff if you are allowed to plug it in. Ask if you can start the engine.
I also keep a list of bank repo car auctions on this site.
Before You Pay
A history report typically will not list mechanical problems. I highly suggest that you pay an independent mechanic to inspect the vehicle before you buy it.
The FTC says this is a good idea even if the dealer already inspected the car. If a dealer will not allow an inspection, the FTC says to consider going to another dealer.
Dealers have to display a Buyers Guide in every used car they offer for sale. It tells you if the car is sold as is or with a warranty.
This is the best and proper way to check a vehicle. If you have any doubts and find any major issues listed above, at all cost do not purchase the vehicle and move on.
Sources I checked
Última actualización el noviembre 13th, 2026 a 04:47 am
