Do modern engines need to be broken in?

Andrew Sluys
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Photos / James Pugsley

Photos / James Pugsley

Seeking out a used car on the second-hand market comes with a raft of variables and niggles that a prospective buyer has to look out for, but running in the engine in isn't one of these. 

Running an engine in only becomes an apparent issue when you have bought a new car, and there's more range in the fuel tank than there are kilometers on the odometer. 

Just last week, I was presented with this exact issue upon picking up a brand new Holden Acadia LTZ V, and noticing a big "21" staring back at me below the digital gauge cluster. After a very unsure Holden worker handed the keys to a 22-year-old who looked far too keen to get on the road (me) I set off. 

It only took a couple of minutes before I realised that this car hadn't actually been properly driven on public roads before, and how I missed my opportunity to ask the Holden employee about the necessary steps to take when a driving a brand Acadia. So, I pulled over and delved into the world of breaking in new engines — courtesy of Uncle Google. 

As with most topics on the internet, there are a lot of opinions floating around that get mistaken for fact when it comes to breaking in these lumps. Despite a lot of backyard mechanics standing by their "drive it like you stole it" mantra, every automotive manufacturer on the planet seems to think differently. 

While most manufacturers offer instructions about how their engines should be broken in over the first few hundred kilometres, Acura in the United States takes the hassle out of the process by running the NSX's engine at low rpm for the first 150 miles before it is put in the car. This is to allow buyers to shoot straight to the track from the dealership, as you do, right? 

Other brands offer advice about keeping engines at a low load, varying the rpm throughout trips, and not using cruise control. Or in other words, don't go giving the thing death right off the bat.

With this new knowledge, I set about making the Friday afternoon trek down to the 'tron from Auckland without taking the engine's revs over 4000 or so. This might sound easier said than done when you've got a reasonably powerful 3.6-litre V6 at your disposal, but thanks to the nature of the Southern Motorway at the end of the working week, it turned out a breeze. I have to add that the incredibly cushy interior of the Acadia made for one of the most comfortable trips I have taken down the line, and those seat coolers were a genuine godsend. 

As most manufacturers recommend that the break-in period shouldn't be any less than around 500 kilometres or so, I obediently remained under that 4000rpm threshold for the remainder of the weekend, resisting every urge to check the straight-line performance of the seven-seater. 

While I can't say that I have a tonne of experience when it comes to breaking in a new engine, the measures that some manufacturers take to ensure that their engines last for years should be more than enough evidence to convince you that it is a necessary protocol. 

I'll leave it to Jason from the popular YouTube channel Engineering Explained to go into the nitty-gritty details of why the breaking in a new engine should be your first priority. 

Click here to view all Holden Acadias on Driven