The importance of a service history in assessing the condition and value of a used car

When buying a used car, service history is one of the most crucial factors to consider. It’s often the difference between purchasing a reliable vehicle and one that could potentially cost you more in repairs than it’s worth. As a car dealer, I’ve seen firsthand the risks associated with buying cars that lack a complete service history. Here, I’ll explain why skipping the service history should be a red flag, backed up by real-world facts and a case study to drive the point home.

What is Service History, and Why Does it Matter?

Service history refers to a record of all the maintenance and repair work that has been carried out on a vehicle. This history typically includes details such as oil changes, brake pad replacements, timing belt changes, and other significant repairs or updates. For most buyers, a full service history acts as a reassurance that the car has been properly maintained and looked after, which can indicate a lower likelihood of mechanical issues down the road.

Without this history, it becomes much harder to assess whether the car has been properly maintained. A lack of service history is often a signal that the car may not have received the attention it required during its lifespan, leading to hidden issues that could surface after purchase.

The Risks of Buying a Car Without Service History

Hidden Mechanical Issues: A car without a service history is a gamble. Many car manufacturers, such as BMW or Audi, recommend servicing their vehicles at specific intervals. Failure to stick to these guidelines could result in premature wear and tear, especially in vital areas such as the engine, suspension, or gearbox. For example, Audi's recommended service schedule is every 10,000 miles or 12 months, depending on the model. Missing these services could lead to expensive repairs like turbocharger failures or engine overheating. Without a clear record, you can’t be sure whether these critical services have been done.

Higher Repair Costs: Cars with incomplete service histories are more likely to have unresolved maintenance issues. For instance, if a timing belt replacement is missed, it could lead to catastrophic engine failure—an issue that can cost £1,000 to £3,000 to repair, depending on the car. For example, in a 2010 Ford Focus, the cost of a new timing belt, including labour, typically ranges between £400-£600. Without knowing when or if it’s been replaced, you could be purchasing a ticking time bomb.

Lower Resale Value: A missing service history can drastically reduce a vehicle’s resale value. Buyers prefer cars with verifiable history, as it provides peace of mind regarding the car's condition and maintenance. A lack of this documentation can lower your car’s resale value by up to 10-15%, or sometimes even more, depending on the model and the buyer's concerns.

Insurance and Warranty Issues: Some insurers or warranty providers may refuse to cover a vehicle without service history, especially if the car is out of its manufacturer's warranty. If the vehicle needs repairs, you could be left with hefty bills, even though the car was sold to you without full disclosure of potential maintenance needs. Without proper history, it's difficult to prove that the car was properly maintained or that repairs were carried out using genuine parts.

Case Study: The Hidden Costs of Buying a Car Without Service History

Let’s take a closer look at a real-world example to illustrate the risks associated with buying a car without service history. The Case of the 2013 VW Golf A customer came to our dealership seeking to sell their 2013 Volkswagen Golf, which they had purchased privately from a previous owner. The car had 80,000 miles on the clock, but unfortunately, it had no service history. Despite this, the customer was keen to get a high price for the car because it appeared to be in good condition.

Upon further inspection, we noticed several issues that were likely linked to the lack of servicing: Oil contamination: Without regular oil changes, the engine oil had become sludgy, reducing the engine's efficiency and leading to excessive engine wear. Brake pads and discs: The front brakes were severely worn, with the discs showing signs of rust and damage due to a lack of proper maintenance.

Timing belt concerns: Although we couldn’t verify when the timing belt was last changed, the age of the car and the mileage suggested it was overdue for a replacement. This is a critical service, as a snapped timing belt can cause serious engine damage, costing upwards of £2,500 to repair. After an inspection and a few quotes from repair shops, the total cost of fixing the car would have been around £3,000—far more than the customer had anticipated. In the end, the customer had to accept a lower offer when selling the car because it lacked the vital service history documentation that would have given buyers confidence in the car’s reliability.

Real-World Data: Why Service History is Essential

National Motor Trade Insurance (NMTI) reports that cars with full service history are 33% more likely to pass an MOT than those without.

According to AutoTrader, 73% of buyers view a full service history as one of the most important factors when purchasing a used car. In fact, 48% of buyers would be unwilling to buy a car if it didn’t have this documentation.

The UK Car Ownership survey by Experian found that used cars with a service history were resold at an average of £2,500 higher than those without, making a significant difference in the car’s market value.

Behind the Scenes: How Dealers Really Value Your Car Using valuation software with Service History

When you bring your car to a car-buying service like ours, there’s often a moment of mystery: “How did they arrive at that valuation?” As dealers, we don’t just pull a number out of thin air — and it’s not all about what your car looks like on the outside either. There’s a method to it, and part of that method is a powerful tool we use daily: Valuation software. In this instance we use a app called 'CAP'

What is CAP? Think of It as the Trade’s Black Book

CAP is the industry-standard vehicle valuation platform. It gives dealers like us real-time access to live market values based on actual sale data from across the UK. CAP doesn’t just give us one price either — it provides three tiers of value for every car:

CAP Clean: For cars in excellent condition, both cosmetically and mechanically, with full verified service history.

CAP Average: For cars with fair wear and tear, part service history, or minor cosmetic issues.

CAP Below (or Low): For cars with visible damage, mechanical faults, missing paperwork, or no service history.

Now here’s the important part: where your car sits between these bands is not decided by CAP — it’s decided by us, the dealer, based on our inspection, market trends, and experience.

Why Service History Makes a Huge Difference

Even if your car looks immaculate from the outside — no dents, scuffs, or scratches — a missing or incomplete service history will almost always drop it down a band in our eyes. Why? Because without that record, we can't verify the car’s mechanical health. And in the trade, if we can’t prove it’s been looked after, we assume it hasn’t.

Plus, we know that unfortunately, service histories can be manipulated. Some sellers still believe that a few stamps in a service book — even without any invoices — are enough to convince a dealer. But we don’t just take the book at face value.

How We Double-Check Service History

To protect our business and give an accurate valuation, we like to double-verify everything. That means checking:

Stamps in the service book

Matching invoices or receipts from garages

Online digital service records (increasingly common for newer cars)

Thanks to systems we have access to, we can often trace a car’s digital service history even if you don’t have the paperwork to hand. For example, many manufacturers like BMW, Mercedes, Audi, and even Ford now log services directly into a national digital system. So, if you tell us the car was serviced at a main dealer but you've lost the invoice — we can often confirm whether that’s true.

No History, Less Money — That’s Just the Reality

It’s not about us being picky or undervaluing your car on purpose. We have to base valuations on what we know — not what we hope. If there’s no way to verify a full service record, the car becomes a higher-risk stock for us. That means it gets placed in the CAP Average or Below category — even if it’s sparkling clean and drives like a dream.

So, from a dealer’s point of view: service history isn’t just paperwork — it’s value. Keeping it all together, with invoices to match, can mean hundreds if not thousands more on your valuation. And in cases where digital records exist, letting us access them could make all the difference.

Final Thought: Don’t Leave Value on the Table

If you’re thinking of selling your car and you’re missing service records, don’t panic — but don’t ignore it either. Try contacting the garage that did the work. Many are happy to reprint invoices or update your digital record. You might even be able to get your service book stamped retroactively if the records exist.

It’s a small step that could give your car a big boost in value — and from a dealer’s perspective, it shows us you’ve taken real care of your car.

Conclusion

In conclusion, buying a car without a service history is always a risk. While the car may look fine on the outside, its true condition can remain hidden. Mechanical issues may be lurking under the surface, which could lead to expensive repairs in the future. Whether it's the potential cost of missed services or the difficulty of reselling the car later on, a missing service history means you’re taking on additional risk that could cost you in the long run.

As a car dealer, I always advise potential buyers to request full service history when purchasing a used vehicle. It’s a small step that can save you a lot of money and hassle in the future. If a seller can’t provide this, it’s a major red flag. And if you’re ever unsure, don’t hesitate to have the car thoroughly inspected by a professional—because when it comes to used cars, knowledge is power, and service history is key.