Low-mileage used cars are safer to buy than high-mileage ones? Not necessarily

If you are in the market for a used car, there is a high chance you have been advised to purchase a low mileage example because it is safer than buying a car that has clocked a lot of miles.

The consensus is, the less a car has travelled, the less wear and tear it picks up, meaning there’s less chance of components failing once you have bought the car.

However, this isn’t always the case, and in certain cases, a low mileage vehicle can pose more issues later on.

This is because the distance travelled by the vehicle only tells you half the story, it does not explain how those kms were clocked, or how long the engine was on to clock said mileage.

A high mileage vehicle that is predominantly driven at constant speeds on the highway will likely have a healthier engine than one that has spent most of its life in stop-go traffic.

Therefore, a high-mileage example doesn’t necessarily mean it’s a bad deal. It is still worthy of consideration as long as it has been maintained properly.

First, let’s define what is low- and high-mileage?

Most manufacturers in Malaysia consider a yearly mileage of 20,000 km to be normal. It is for this reason, manufacturer warranties usually read 5-Years/100,000 km, whichever comes first. One applies to the low-mileage user, and the other for the high-mileage user.

Therefore, if a car travels considerably less than the stipulated 20k km/ year, or approximately 55 km per day, it is considered low mileage.

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Typically, a car that has approximately 80k km or less after 5 years will be considered a low mileage unit, if it has covered 120k km or more after 5 years, it can be considered high mileage.

However, mileage is just one part of the equation

As we’ve said, mileage only tells you half the story. Consider the following example, in both cases, we assume a constant that both cars are driven for 90 minutes per day.

The examples show that while the mileage of car B may be lower, the usage hours of the car will not differ by much. 

Regardless of how far the vehicle travels, the engine, transmission, charging system, air-conditioning and cooling systems all remain operational. Thus, wear and tear still occurs.

Furthermore, the higher mileage vehicle would have changed its engine oil at least 12 times versus 5 times the low mileage car, over the same period of time.

If it has been driven further, more things can go wrong

This brings us to our second point of discussion, how the vehicle is used.

• Low mileage vehicles

Lower mileage vehicles are typically driven within the city, hence, even if they don’t travel far, they are still subjected to stop-go traffic and typical Malaysian heat.

In stop and go traffic, the transmission is required to change gears more frequently as the car speeds up and slows down, putting additional strain on the car's drivetrain.

There is also less airflow to the car’s radiator, which requires the cooling system to work harder, it’s much the same with the air-conditioning system. On a hot day, these issues are further compounded.

A separate issue is oil condensation. If a car is driven primarily on short trips and the oil isn't brought up to normal operating temperature, condensation occurs and introduces moisture into the oil.

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If the car is driven long enough, the engine will burn away this moisture, however, if the engine is turned off before this happens, this moisture build-up eventually creates acids that degrade the oil.

It normally takes about 15-20 mins of driving for an engine to properly warm-up, and a bit longer than that for the moisture to burn off.  

• High mileage vehicles

In high mileage vehicles, typical use will include a substantial amount of highway driving.

When a car is driven long distances, the engine operates at a constant speed, making it more relaxed and efficient. The transmission also does not have to cycle up and down through the gears quite as much.

At higher speeds, a vehicle receives increased airflow through the radiator, meaning both the cooling and air-conditioning systems don’t have to work as hard.

It’s much the same with lubrication – the longer distances allow the car to properly come up to temperature, and provide the best care for the engine.

Don’t higher mileage cars require more maintenance?

In a nutshell, yes, the more mileage a car incurs, the more wear and tear occurs.

However, if these maintenance or service components, e.g.: lubricants, belts, filters, tyres and suspension components are replaced on time – a car will continue to perform smoothly and safely.

A common issue with low mileage cars is that periodical services tend to be dragged on until the actual mileage is reached.

This is why certain manufacturers impose time intervals for their service schedule. We quite often find service intervals 10,000 km / 6 months or 15,000 km / 1 year.

What’s worse, is if the time interval is ignored and services are only conducted when the car hits the stipulated mileage.

Over time, the petroleum-based oils and additives that make up a car’s engine oil break down (due to heat and pressure within the engine) and can no longer protect the engine’s components, increasing wear and tear and sludge build-up.

Therefore, a higher mileage vehicle, that gets its lubricants replaced regularly, will have lower levels of sludge buildup and carbon deposits within the engine, further increasing its lifespan.

Conclusion

Searching for a perfect used car is a tedious process, however, prospective buyers should not limit themselves to just low mileage cars.

Higher mileage cars are still worthy of consideration if maintenance has been performed on time and components change as required. It can also mean the engine is healthier and more adapted to being used.

In addition to familiarizing yourself with a vehicle’s maintenance schedule, a comprehensive service history is invaluable in determining just how well a car has been maintained and what to expect once you have purchased the vehicle.

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