BMW 318 vs. BMW 320: which is better?
BMW model numbers are confusing but the 318 and 320 are the most common. But which should you buy?
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If you’ve decided that a 3 Series is the right model for you, then you’ll be faced with a variety of engines and trim levels.
With so many to pick from, including 316, 318, 320, 325, 328, 330, 335 and 340, making a decision can be overwhelming.
We spell out the key differences between two of the most popular versions – the 318 and the 320 – to help you decide which is right for you.
Styling
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BMW models get their names from the series and the engine, so in the case of the 318 and 320, both belong to the 3 Series, which is available in saloon and estate formats.
In the case of these models, the specific version of the 3 Series in question is the F30 saloon and the F31 estate, which were sold between 2012 and 2019.
Compared to similar-sized cars like the Audi A4, the 3 Series looks much sportier thanks to its aggressive styling and characteristic grille and front-end design.
The 3 Series also has a distinct LED daytime running light pattern, so even in the daytime, it looks fairly unique.
The 318 and 320 models are available in a variety of trim levels, and these are what make each car look different.
Even basic SE models look great, but M Sport versions are the most head-turning, with sporty details inspired by the performance M3.
What are they like to drive?
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The 20 and 18 parts of the names refer to the engines under the bonnet, and they’re available in petrol (318i/320i) and diesel (318d/320d) formats.
The petrol models use different size engines – a 136hp 1.5-litre unit for the 318i, and a more powerful 184hp 2.0-litre engine for the 320i.
The engine technology for the 320i changed in 2015, so look for a newer model for the best efficiency.
The diesel 318d and 320d versions both use 2.0-litre engines, which produce 143hp and 184hp, respectively.
These also got a 2015 upgrade, and with it, a boost in power. The 318d models went on to make 150hp, while the 320d models got 190hp.
BMW still uses the upgraded engines in many of its cars today, which is a testament to how smooth and efficient they are.
The same is true of both the 318i and 318d in that they’re designed to maximise efficiency, so they’re not particularly quick.
If you prefer some more pace, the 320i and 320d models are as quick as some hot hatches, and they make more sense in cars of this size.
It’s worth noting that the 320 models were also available with some efficiency improvements – look out for EfficientDynamics (or ED) models, which provide the best of both worlds – power and fuel economy.
Rear-wheel drive is the setup of choice for the 3 Series, which can be more confidence-inspiring and even fun, so they stand out against less exciting front-wheel-drive cars.
There are some four-wheel-drive models available if you need the added grip, but this hinders fuel economy slightly.
They’re badged xDrive, and they’re only available on the two 320 models (or other versions of the 3 Series with more powerful engines).
Interior and technology
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Again, there’s nothing that separates the interior of the 318 from that of the 320, but higher trim levels do have more equipment.
The interior of every model uses high-quality and soft-touch materials, so the 3 Series is a noticeable step up from many typical family hatchbacks of that age.
As part of the 2015 update, the interior was also revised. These newer models have larger iDrive infotainment displays and more equipment as standard, plus a smart-looking gear selector for the automatic versions that returns to the centre after selecting a gear.
The difference between pre-update and post-update models is fairly considerable, so it’s worth paying a little extra for a newer model if you can – even if that means going for a less powerful 318 engine.
Boot space and practicality
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Both models have a 480-litre boot, even if you go for a four-wheel-drive version of the 3 Series, which means you get around 100 litres more than you would in something like a Volkswagen Golf.
It’s worth paying attention to how the boot opens because as with any other saloon – including the Mercedes C-Class – it has a narrow opening that’s less practical for loading bulky items than a hatchback-style boot.
For reference, the plug-in hybrid 330e model has a smaller 370-litre boot.
The estate version, badged Touring, only has a slightly larger boot, at 495 litres. However, it has a more useable hatchback boot opening, so you can slide big items in with more ease.
Reliability
BMW cars are premium products, and as such, they’re built to last.
However, they’re not immune from any of the same maintenance issues that affect any other car on the road.
When it comes to replacing parts, including tyres, you might find yourself paying slightly more than the average.
Issues with the car aren’t too common, but because the diesel models have a DPF to reduce harmful emissions, you’ll need to drive long distances fairly regularly to prevent it from clogging up.
This goes for any modern diesel from any manufacturer.
Because the 3 Series came with a three-year warranty, you won’t find any with the original manufacturer warranty remaining anymore, but you may wish to consider a used car warranty for peace of mind.
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Size and dimensions
The BMW 3 Series is 4,624mm long, 2,031mm wide and 1,429mm tall, which means it’s close in size to the Mercedes C-Class.
Verdict: BMW 320 vs. BMW 318: which should you buy?
Both the 318 and the 320, whether in petrol or diesel form, are about as efficient as each other in the real world.
However, the extra power of the 320i and 320d models makes lighter work of moving the mid-size saloon and estate, and we think they’re the better option for more drivers.
Fortunately, a lot of buyers thought the same when they ordered their cars from BMW, so there are plenty of 320 models to pick from when looking for used cars.