Believe it or not, there was a time when it was common to see new cars driven slowly with a 'running-in, please pass' sign in their back windows. No need for anything this drastic now as cars are better engineered and better put together, while modern engine oils are much more sophisticated.
Reliability, oil consumption and fuel consumption can all benefit from a little extra care early in a new car's early days, though. Ask the dealer for advice and check the handbook – many still include some 'running-in' advice.
For the first 1,000 miles...
- Start with gentle driving around town so everything, including brakes, can bed in.
- Avoid harsh acceleration and heavy braking if you can.
- For diesels, keep engine revs below 3,000 rpm, but make sure they regularly reach this limit.
- For petrol, try to stay below 3,000 rpm for the first 500-600 miles and then increase the limit to around 4,000 rpm. Again, revs should regularly reach this limit.
- Avoid labouring the engine by changing up too early or using too high a gear.
- Check oil and coolant levels at least weekly – this is a new car so you don't know how much oil it'll use. Oil consumption can be high for the first 6,000 miles or so but should slow, particularly if you treat the car gently to start with.
- Brand new tyres have a thin oily coating (mould release agent from when the tyre was made) – this can affect handling but it wears off within 3-5 miles.
- After the first 1,000 miles gradually use more of the car's performance.