There’s been some debate recently in regards to the correct ‘break-in’ procedure for a new car. Traditionally, the recommendations for ‘breaking-in’ an engine were to ensure no more than 1/4 throttle and gentle revs for at least 1,000 kilometers. In the old days this was a golden rule, but has it now been rendered obsolete or does this method still apply?

In the past, engine manufacturing wasn’t as precise as it is now, bear in mind we’re taking about precision to the thousands-of-an-inch. As a result, a gentle break-in allowed various metal parts, which had minute imperfections, to interact with one another and wear themselves in. Now that engine construction is highly advanced and tolerances are much more precise, this isn’t required quite so much anymore. Nevertheless, how you treat your engine in the early stages can determine its long term health and is therefore still important.

Does this mean, then, that by simply being gentle, you can ensure longevity for your car’s engine? Well, here’s where it gets a little complicated. Some new-age experts suggest that by being gentle you could actually cause more harm than good.

They point out that while engine construction has improved, you still need to seat the piston rings. The piston rings essentially work to keep the combustion chamber completely sealed – ensuring that combustion gasses don’t escape into the crankcase. During the break-in period, the piston rings mould themselves perfectly to the exact shape of the cylinder walls and keep your engine running cooler and cleaner – once again we’re in the realm of thousands-of-an-inch or even ten-thousands-of-an-inch.

These experts, therefore, suggest a ‘hard break-in,’ which is to say they recommend a few runs to the upper limits of the rev range in order to generate enough cylinder pressure to effectively seat the piston rings. Theoretically this seems plausible, but you’d be hesitant to take such liberties in your brand new car – especially since most manufacturers still recommend refraining from exceeding 4,500rpm (in a petrol engine) and making full throttle starts during the break-in period.

Proponents of the ‘hard break-in’ method argue that manufacturers recommend the traditional method because they want drivers to better acclimatize themselves with their new car, and its characteristics, before getting fully acquainted with the extremities of the accelerator pedal. We tried getting in touch with a few manufacturers to get their take on this issue, but they seem reluctant to comment. However, technical experts at VW unequivocally point out that no special care is needed to ‘break-in’ a new VW. On the other hand, they do mention, “The customer should always drive more carefully in the initial weeks till he or she is totally accustomed to the new car and its controls.” And like practically all other manufacturers, they encourage reading and understanding the Owners Manual, which is an important but largely ignored practice by most new car buyers.

Most experts at the manufacturers end point out that modern engine construction actually ensures near perfect ring sealing from new, and therefore no effort needs to be made by the driver to ensure this.

Thankfully, there is some consensus amongst these different groups. Firstly, they all recommend that drivers make an effort to constantly vary the engine revs during the ‘break-in’ period. For instance, driving on the highway in a single gear at a constant speed is a decidedly less than ideal way of breaking in a new engine. They also warn against putting the engine under excessive strain by towing another vehicle or even under-revving the engine, which is to say driving at a low speeds in a high gear.

Essentially, it boils down to this – drive as you normally would, but be sure to vary engine revs. An occasional trip to the far reaches of the rev range won’t hurt – but when accelerating, do so gradually, which is to say avoid moments of full throttle exuberance. And lastly, ensure that the engine is fully warmed up before you display any signs of enthusiasm whatsoever – in fact, this holds true well past the engine break-in period as well.