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8 Oct 2020

5 driving mistakes that raise your motoring costs

Running a car is undeniably expensive, but changing your driving habits could see you avoid unnecessary expenses

You could be making some basic mistakes causing your car to operate less effectively. Our experts reveal the common errors that cost you more overall in fuel and maintenance costs.

The fact that running costs are so important to car owners isn't lost on manufacturers. Each successive month sees a raft of new hybrid and plug-in models, claiming to offer implausibly high mpg figures, as well as tax-friendly CO2 emissions.

But if you're not in a position to change to a brand new car, you can cut costs in other ways. Read on to find out which basic errors you should be avoiding to reduce the potential for big bills.

A Which? Best Buy model not only has to be efficient, but safe, reliable and comfortable, too. Find out which cars, new and used, will suit your needs best. See our best cars for 2020.

1. Labouring the engine

Low revs means low fuel consumption, right? This is certainly true up to a point, as keeping your engine in a higher gear will indeed reduce fuel consumption. Although if you select too high a gear at too low a speed (drivers with automatic gearboxes needn't worry about this), the engine will become laboured.

You'll notice that acceleration becomes very sluggish, and there's a lot more engine vibration as it struggles against the higher gear ratio. Ever tried to pedal a bicycle in a high gear at low speeds? That's exactly the strain your engine is going through.

Labouring the engine not only needlessly puts extra strain on critical (and expensive) engine components, such as the crankshaft, it will also cause the engine's computer to inject more fuel in an attempt to keep it from stalling.

Many new manual cars have a gear-change indicator, which shows the ideal time to change up or down. However, these don't always take into account your surroundings (if you're driving up a hill, for instance). So it's always best to use your own judgement.

Find a new car that won't let you down, and avoid the ones that will - we reveal the most reliable cars.

2. Riding the clutch

Another mistake to avoid in a manual car is resting your foot on the clutch pedal when not changing gear. It's a lazy habit, particularly when many cars now have a footrest just to the left of the pedal.

Even the slightest pressure on the clutch pedal can cause the clutch plates to disengage slightly as you drive along. This will quickly accelerate clutch wear, and can more than halve its usable life.

Replacing a clutch is a labour-intensive job which could generate a four-figure bill, depending on your car.

Automatic gearboxes are available in nearly all new cars - find a model that's right for you with our new and used car reviews.

3. Avoiding basic maintenance

Skipping minor services, such as oil changes, can be a tempting way to save cash, but in reality it's a false economy.

Oil, in particular, is essential for a healthy engine, as it's required for lubrication and cooling. As you add miles to your engine, oil picks up deposits from the combustion chambers, reducing its effectiveness over time. This can increase both fuel consumption and engine wear.

Oil and filter services are among the cheapest maintenance you can carry out on your car and, if you're that way inclined, they're relatively simple jobs to carry out yourself. Just be sure to check you're using the right oil by consulting your vehicle's handbook.

Similarly, if you notice uneven wear on your tyres, don't ignore it. It's a sign that your wheels are misaligned. This will not only mean that the tyres will become worn to illegal tread depths more quickly, your car also has to burn more fuel dragging it along the road at an imperfect angle.

Need to find a trustworthy mechanic? Check out our advice on how to find a good garage.

4. Buying the wrong tyres

Buying the correct tyres for your car is as critical for safety as it is for minimising costs. All of the accelerative, braking and turning forces generated by your car are transmitted through those four small rubber contact patches, so it pays to buy the right ones.

That's not to say you should overpay for a high-performance tyre you don't need. Unless you've got a high-performance or sports car, it's unlikely you'll need very expensive tyres.

Sports tyres are often made of softer compound rubber. This enhances grip, but can wear more quickly than more mainstream tyres. They're also expensive because they're rated for travelling at higher speeds - which may be unnecessary, depending on your car and where you use it.

Similarly, purchasing part-worn or remoulded tyres should be reconsidered. They're often available at a significant discount to new rubber, but are in effect second-hand. That means they're more liable to developing faults and wearing out more quickly.

They may also not perform as well under braking - meaning the money you've saved could well be wasted on your insurance premium in the event of an otherwise avoidable bump.

Check your existing tyres or consult your vehicle handbook for the recommended brand, size and speed rating for your new tyres.

Head to our guide on which car tyres to buy, for more information on the types of tyre available, and how to decipher their ratings and markings.

5. Keeping heavy items in the car

Keeping spare tools or other items in the back of your car only adds weight, which will have a negative effect on your fuel economy.

Try to carry only essential items and remove cycle carriers and roof boxes when not in use. These can play havoc with a car's aerodynamics, reducing the efficiency with which it cuts through the air. It may have a small impact on fuel consumption, but the costs will mount up over time.

Need a car with a big boot? Find out which models aced our tests in our guide to the best estate cars.