By Anthony Santiago - Editor-in-Chief

March 17, 2023
7 red flags for used cars

I know from first-hand experience how NOT to buy a car, despite the seller being a family friend. I will cover exactly what you must look for to avoid these 7 red flags for used cars.

When buying a used car, you must be very objective about what you see in person. Some tell-tale signs will indicate that you need to move on and walk away. Knowing what to look out for can save you time, money, and hassle in the long run. Trust me; these are some important things to consider.

From mismatched paint jobs to suspiciously low prices, this article will discuss 7 red flags to watch out for with a used car.

Best Reason to Consider Buying a Used Car

You probably already know that buying a used car is often a great way to save money while getting reliable transportation. Yes, used cars can offer more bang for your buck, with some of the same features and amenities as newer models at a fraction of the price.

The BIGGEST advantage is that you don't have to worry about taking an immediate hit in value due to depreciation that occurs when buying a new compared to finding the right used car.

There are good deals to be found via private sellers and dealerships. But you need to be aware of some red flags.

Red Flags to Look Out For

While buying a used car has plenty of benefits, it's important to know what potential red flags to look out for.

  1. Lack of Maintenance History
  2. Salvage Titles and Accidents
  3. Dash Lights and Inspection Sticker
  4. Engine Startup and Exhaust Color
  5. Weird Noises and Smells
  6. Low Prices
  7. Rust, Dull Paint, and Wavy Bodywork

1. Lack of Maintenance HistoryService Record

Whenever I look at a used car, I always check the vehicle history report for service records. By reviewing the service records of the previous owners, I can see how the car was maintained and where it was serviced.

Dealer service and maintenance are preferred, but a specialty shop indicates that the owner cared for the car.

However, if you see JiffyLube or a general auto shop, the good news is that at least the minimum was done. I typically shy away from cars with these owners, but sometimes, it might work out.

TIP: If you see a repeat of the same repair listed recently, it might clue you in on a recurring issue. If you notice missing maintenance or servicing, ask if the seller is a DIYer. They might have serviced the car themselves.

If they are DIY, ask for receipts or invoices for purchased parts. As a car owner, I have a folder full of receipts I have purchased over the years.

In addition to checking for regular oil changes, brake inspections, and tire rotation services, also be sure to look for any major repairs that may have been done in the past. You might also google "Miles servicing" for your model.

For example, if the car has 57K miles, google 60K mile service to see what needs to be done and compare it to the vehicle history report. By going through the service records, you can determine whether or not all necessary maintenance has been performed on the vehicle - so take your time and ensure nothing is overlooked!

Number of Previous Owners

Doing your due diligence when researching the previous owner of a used car is essential.

Try to find out how long they owned the car, how often they drove it, and if they performed the regular maintenance. You can tell a lot from the car's condition and how they present itself.

If it is a family member's car, see the story behind why they are selling.

Red flag: If they only had it for a short time or put a few miles on it, this could indicate an underlying problem with the vehicle.

Cross-reference the Carfax report can help ensure there aren't any hidden surprises waiting for you after purchase—and if all else fails, having a qualified mechanic do a pre-purchase inspection (PPI) can alert you to any immediate issues that need attention before you commit to buying the car.

To learn more about a PPI, check out our article, What is a PPI for a Used Car?

Watch Out Questionably Low Mileage

The average miles driven per year is between 10k to 12 k miles.

When it comes to used cars, low mileage is a double-edged sword. On the one hand, you may be getting an almost-new vehicle at a fraction of the cost, but there could be hidden issues lurking beneath the surface.

Low miles could indicate that the car was not driven much due to a mechanical or title issue. The title issue might be salvaged or rebuilt since it was off the road for many months.

Secondly, if it was not driven for months, find out why. If you are lucky, you might only have a weekend car but only know if you ask.

By taking these extra steps before signing off on a purchase, you can save yourself from any costly surprises down the line!

Look for Signs of Neglect or Poorly Made Repairs

No matter how well you research before buying a used car, some signs of neglect and corner-cutting repairs may be easy to miss. These are the kinds of red flags that can end up costing you more in the long run if left unchecked.

In addition, neglect like trashed interiors and dirty trunks can give you a better idea of how the car might have been cared for or lack thereof.

Look under the hood for tape or zip ties that show that corners were cut with mounting parts correctly.

If any of these signs raise alarm bells for you when looking for a used car, it might be best to walk away or negotiate further before committing to purchase. With just a bit of extra effort upfront, you'll save yourself from potential headaches down the line!

Buying a used car can be a great way to save money, but it's important to be vigilant in looking for any red flags that may indicate problems. If you watch for the tell-tale signs of neglect or corner-cutting repairs, you can make a more informed decision and rest assured that you're getting a reliable car. Now, look at one major sign of trouble—mismatched tires & hubcaps!

Mismatched Tires and Hubcaps

One of the most common signs I look at is the tires.

Mismatched tires indicate the owner did not budget or care that the brands or model tires matched. It is a clear sign of poor maintenance.

In my free guide, my rules are that 2 brands can be mismatched. But if all four tires are different brands, I would tread carefully since the owner didn't care about the tires in general.

I always check if all the tires are the same size and type. In addition, I check the DOT and the condition of the rubber. While they might not be a deal breaker, they can affect handling and braking performance.

If you notice that they're different, ask the seller why?

Ultimately, if there are mismatched tires on a used car you're looking at, consider that before making a purchase decision. A new set of four tires can cost between $500 - $1,200.

2. Salvage Titles and Accidents

Vehicle History Reports

Vehicle history reports are an invaluable tool for buying a used car. These reports provide detailed information about the vehicle's past, including its accident, ownership history, and any reported service or maintenance issues.

When you receive a vehicle history report, look for red flags, such as previous accidents or title problems, that may indicate the car has been damaged somehow.

Red Flag: I would avoid salvage or rebuilt titled vehicles if you are unfamiliar with these branded titles. Your insurance company might reject coverage.

You should also check for open recalls, which may give you insight into any potential safety issues with the car.

Accident Damage & Damage History

Unfortunately, accidents happen constantly; if they are reported, they will be listed in the vehicle history report.

If the repairs were done properly, this could sometimes be hard to spot, so you'll need to take some extra time to inspect the car's exterior for any signs of repair work. Poor workmanship can be mismatched paint color and wavy paint surfaces.

Pay attention to misaligned panels, inconsistent gaps between doors and windows, and mismatched paint colors. These could indicate that the car has been in a collision at some point if the accident was never reported.

Regarding the paint, if something doesn't look right or seems suspicious, it may be best to walk away from the deal altogether.

Researching a car's damage history is essential for any responsible buyer, and it could save you from making a costly mistake.

3. Dash Lights and Inspection Sticker

When buying a used car, one of the first things you should do is turn on the engine and check for any warning lights on the dashboard.

That said, I always look at the dash lights when I look at a used car I am considering purchasing.

The vehicle should start up easily and quickly. If there are any dash lights, I would ask the seller about these.

Today's modern vehicles have many sensors, and if there is anything out of range with the air-to-fuel ratio, it will commonly trigger a check engine light.

The most common reasons for dash lights are emission related. If the car runs smoothly, it might be a minor issue of a bad oxygen sensor, spark plugs, or ignition coils.

If you spot any warning lights, ask about them and why they're present.

If it is SERVICE soon, It could be a minor issue such as needing an oil change or brake pad indicator.

However, if the car is running rough and is smoking out the exhaust, it could indicate a bigger problem.

4. Engine Startup and Exhaust Color

Upon startup, the exhaust might be white due to the moisture and condensation in the exhaust. But it should not continue to smoke, and the water vapor should dissipate quickly. Any other colors from the muffler might indicate an underlying problem with the car.


Here are some signs that can help tell you what the potential issue might be:

  • Blue smoke- Blue smoke shows the car burns oil in the combustion engine. This might be due to damaged cylinder heads and bad piston rings that allow blow-by. This is a big job, and I would avoid the vehicle if you see this.
  • White Smoke -White smoke on startup normal. However, plumes of white smoke with a sweet smell can indicate that coolant is being burned, and it can possibly be a bad head gasket. If the smoke continues to thicken as it billows out, it may be a bigger problem and headache to fix.
  • Black Smoke - Black smoke means it's burning and rich in excess fuel. It could be a MAF error or injectors. If you notice this, I will avoid this since injectors can be an expensive part to replace.

Missing or Failed Emission inspection

7 red flags for used cars - no inspection

Failed emission inspections can be a huge hassle for used car buyers. The good news is commonly an ignition coil issue or an o2 sensor. Both of them are relatively quick and cheaper fixes. However, the bad news is that it can be costly if the problem needs to be caught early enough.

If the vehicle normally drives, using this check engine light might be ok to negotiate the price. An OBD scan of the car will quickly identify the potential issue for the dash light.

When buying a used car, always check the vehicle's CarFax report to see if it has failed any emissions tests in the past. If it has not been addressed, this could indicate a potential engine or mechanical issue that was too expensive to fix for the seller.

TIP: Do not believe if the seller says it's a fuse or something. If it were a cheap fix, it would have been done already.

Remember, if your vehicle fails its emissions inspection, you must have it repaired before legally driving it on public roads. A failed inspection has 30 days to repair and reinspect the car.

Parts like a bad catalytic converter or head gasket can outweigh the cost savings and are hefty repair bills. Therefore, ensuring that any used car you're considering has passed its emission inspection before agreeing to buy it is important.

No Inspection

If the inspection sticker is expired or missing, you will want to ensure that you have the car looked at by a mechanic with a PPI or scanned with an OBD scanner to check for fault codes. An expired sticker might indicate that the car was not driven for many months or years.

I always want to purchase a running and driving vehicle unless I plan to part out or have a project car. No matter how tempting, only buy a used car with an inspection done first. It's the only way to ensure you're getting a quality vehicle and not being taken for a ride. 

5. Weird Noises and Smells

When it comes to buying a used car, the smell of the vehicle can tell you a lot about its condition and history. It's important to use all your senses when inspecting a used vehicle – including your nose!

If you notice an unusual weird smell inside the cabin, it could indicate that the car has been flooded at some point. Water has a very distinct smell if it sits. If you have any whiff of mold, it's there. You should also check under the hood for corrosion or mold growth signs. These things indicate that the car may have been in contact with water at some point and, therefore, should be avoided if possible.

There are ways to mitigate it, but you need to negotiate the price for a professional detail, or you can follow the steps listed here regarding removing smells in your car.

The vehicle might have an unpleasant odor if the previous car owner was a smoker. Such smells can be difficult to remove, but with time it is possible to lessen them significantly.

By following these tips, you can be sure to make an informed decision when it comes to buying a used car. So remember to trust your nose - it may just give you the necessary answer!

Do You Smell of Mold or Mildew?

7 red fags for used cars - mold

Mold and mildew can be a big red flag for used cars. Not only is it unpleasant, but it could indicate that the car has been exposed to water at some point. If you notice a musty smell, look for signs of discoloration or corrosion – both water damage indicators. Also, check underneath the car for any signs of rust or mold growth.

Water damage in a vehicle can significantly damage mechanical systems, electronics, and lubricants, which may prove costly to repair. Therefore, it is vital to consider any warning signs of water damage. This can be incredibly expensive to repair, so taking these red flags seriously is important. When purchasing from a private seller, inquire about the source of any odors and if any repair work has been done on the vehicle.

It's important to remember that mold and mildew can be a big red flag when it comes to used cars.

TIP: I have purchased cars with some water intrusion. I knew what I was getting into and could fix the problem after repairing the window vapor barrier and tail light assembly.

6. Low Prices

If it's too good to be true, it usually is.

Finding a great deal on a used car is every driver's dream. But it would help if you were wary of any vehicle with an unbelievably low price tag.

The seller might be offloading a problematic vehicle to the next buyer. Before signing any paperwork, check the average market value of the make and model to compare prices. If something seems way off, then it's likely because there's something wrong with the car.

From experience, low-priced cars have engine issues, salvaged titles, or transmission issues. It will usually say "mechanic special" or something similar. The other tactic is to list "$3,000" for a new car, but that is typically just the downpayment, and the full asking price is thousands of dollars more.

When it comes to used cars, always trust your gut—if the price feels too good to be true, it likely is! But don't forget to look out for rust or other damage that could lower the car's value even further.

7. Rust, Dull Paint, and Wavy Bodywork

Rust or Other Damage

Rust and other forms of damage can often be hard to spot, especially if you don't know what you're looking for. Rust is caused by exposure to the elements over time, so looking at more exposed parts—like the side skirts, wheel wells, and the trunk area is important.

Rust can form under the paint and cause blistering. The bad thing about rust is that it can continue to spread without you knowing. This can impact the subfloor and the frame of the car, as well as other components. You should grade the car in Good or Fair condition based on any rust issues.

Rust on fenders can be replaced with a new fender, but rust on the body panels can be costly to repair.

These things can add up to a lower resale value and might not be worth investing in.

Mismatched Paint & Window Sticker

Mismatched Paint & Window Sticker

One of the most important things you should look for when buying a used car is mismatched paint and poor bodywork. The paint should be smooth and not wavy. Cross-reference the vehicle history report for accidents and check the areas for poor workmanship.

It's possible that the car has been in an accident or suffered some other type of damage and then repaired with parts from another vehicle. But the paint should match pretty well.

If you are ok with not-so-perfect paint, you can also use that as part of your negotiations.

Final Thoughts on Red Flags

I've shared my experience and insider tips on what I look for in a used car. These red flags are not the end all be all, but these are my special deal breakers for me.

As I mentioned in many of my articles, more opportunities will always exist to find another vehicle. If you follow these steps and the checklist in my Top 3 Rules for Being a Used Car, you will be well on your way to finding a great deal with your next vehicle.

If you have any questions, please reach out or comment below. We love to hear from our readers.

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Anthony Santiago - Editor-in-Chief

About the author

I am a passionate car enthusiast who likes to help people save money and avoid headaches when it comes to cars. I believe that everyone can find the right car at the right price. I share my tips and experience so you can learn quickly and maximize your next SUV, truck or car purchase.

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