What Car? Q&A - Do you still need to 'run-in' new cars?
A: Most new cars don't require running-in, but you certainly won't do your engine any harm by taking it easy for the first few hundred miles.
It's worth checking your car's handbook to see if there's a specific running-in procedure, though. If you can't find anything in there, ask your supplying dealer if it's necessary.
The idea behind running in an engine is to allow time for the mechanical parts to bed in before they are put under stress. This typically means limiting the revs for the first thousand miles or so. Doing so can dramatically increase the life of an engine.
This used to be the responsibility of the owner, but many modern car engines either don't require running in, or the procedure is done on a 'bench' at the factory.
If you want to be careful, though, keep your engine's revs low for the first thousand miles or so. Change gear as early as you can and keep speeds low during this time and you'll go a long way to extending the life of your engine.