Is New Engine Break In Procedure Still Necessary?

Do today’s new engines still need a “break-in” procedure? Or just drive it normally and do the first one or two oil changes early?
I’m interested in what the GM owner manual suggests and also what real world engine builders/mechanics think.
I’ve read some guys say that “taking it easy” for the first 500 miles just glazes the cylinders and doesn’t let the rings wear in properly or fast enough. The theory is that you should drive it hard and vary the RPMs right from the start (after reaching full operating temperature of course).
What do you all think? Is new engine break-in a thing of the past?

This is a good question, but unfortunately, I do not have the answer.

The last new vehicle that I had was a 2015 Honda, and I changed the oil early, based on traditional engine break-in theory. I was reprimanded by the dealer for the early oil change, stating that the first batch of oil in the engine was a special break-in blend of oil that was designed to go the full mileage until the first oil change.

Let's see what other folks have to say here.

Fairweatherider said:

Do today’s new engines still need a “break-in” procedure? Or just drive it normally and do the first one or two oil changes early?
I’m interested in what the GM owner manual suggests and also what real world engine builders/mechanics think.
I’ve read some guys say that “taking it easy” for the first 500 miles just glazes the cylinders and doesn’t let the rings wear in properly or fast enough.
The theory is that you should drive it hard and vary the RpMs right from the start (after reaching full operating temperature of course).
What do you all think? Is new engine break-in a thing of the past?

Click to expand...

I'd be willing to bet lots of money that I don't have, that GM does not bother with 'break-in' motor oil,
they just use a Mobil1 factory fill that anyone could find at any auto parts store.

If that's the case, then, simply because I'm an overcautious pessimist,
I'd look up the break in procedure for GM's LT4, and use that.

Actually, if it has Engine Confusion (DFM), I'd entirely avoid this feature and drive in L9 during the break-in.
Soon as you can find a DFM disabler (or even a minimizer), I'd install it pronto.

Don't forget to change the ATF & differential fluids after their break-ins as well.
It's an opportunity to find and use other upgraded fluids that would still be warranty-approved.

Do your very best not to drive at any engine RpM or road speed 'constants'.
The more variable you drive it, the better the break-in. Push it, but don't shove it - be sensibly aggressive.
I'd keep it under 4750RpM til after the 1st oil change.

Best thing you can do is do not take short 15 minute trips, depending on the outside ambient temp the engine oil in these engines can take up to 30 minutes to match the engine temperature.

Even a 4-8 mile vehicle will have fuel in the oil. Pull the dipstick and check and smell for yourself.

I would try to get the vehicle on the highway for a 45 minute drive to fully warm the engine oil.

If you are getting a 6.2l run Premium fuel in it.

Thing to consider

And if I do smell oil on the dipstick, should I drive it to burn the fuel out of the oil, or should I stop and do an oil change? I understand that this is a DI engine, and that fuel in the oil is a side effect of excessive idle time. I've never owned a DI engine, so I don't know anything more than that.

Fairweatherider said:

Do today’s new engines still need a “break-in” procedure? Or just drive it normally and do the first one or two oil changes early?
I’m interested in what the GM owner manual suggests and also what real world engine builders/mechanics think.
I’ve read some guys say that “taking it easy” for the first 500 miles just glazes the cylinders and doesn’t let the rings wear in properly or fast enough. The theory is that you should drive it hard and vary the RPMs right from the start (after reaching full operating temperature of course).
What do you all think? Is new engine break-in a thing of the past?

Click to expand...

I recommend changing oil and filter at 25 hrs or so on the engine. You can see what drained out on my first oil change at 25 hrs… nothing better than a pic to look at.. zoom up on it and you can what came out…

[Rant]
How hard would it be for GM to break in each engine before installation?
Thanks for nothing.
[Rant over]

Judging by the engines that come straight out of the box from GM, I get the feeling that GM has stopped even doing cold running-in. So, running-in is vital, and after it, you should change the oil, somewhere around the first 1000 miles.

@Fairweatherider

Fuel contamination can be managed, however, it can also become cumulative depending on the weather and driving conditions.

Best way to manage the problem is make sure you are driving regularly 30+ minutes straight and/or get on the highway for 30+ minutes, probably at least once a week.

Short 10-15 minute trips, regularly using using the Remote Start feature or starting the engine and allowing the engine to warm up without driving either in the Winter or Summer clearly puts more fuel in the engine oil. I believe the Auto Stop/Start feature will also contribute to more fuel in the oil as well. Excessive idle time can also be a contributor to fuel contamination as well due to idle being a richer mixture when compared to cruise mixture.

If you are running 5W30 or 0W40 oil you also have at least a bit of safety margin for fuel contamination in the crankcase as well. As fuel contaminates the engine oil its viscosity is lowered.

As always, manually check the engine oil every 2nd to 3rd fuel fill up for proper level and also smell the oil for traces of fuel. Once you get your nose trained for fuel detection, you will be in a better place to understand how your driving habits may contribute to fuel contamination in the engine oil.

Back to the original question about break in oil, from initial oil analysis it appears that the factory fill has a higher level of Moly in the oil. Unclear if this is due to Moly coatings on the camshaft or bearings, Moly assembly lube or an oil with Moly additives. Moly is a good friction proofing/lube additive.

Personally is you plan on running something other than 0W20 engine oil, I would change the oil ASAP. Even if you plan on running 0W20 oil, I would change the oil by 10 hours or before 500 miles. Get a magnetic oil drain plug, search my user name as I have a thread on this.

There is a good oil on the market that has a high Moly content, but it is not officially Dexos approved, but pretty much meets the Dexos requirements. There are licensing issues and oil formulations need to be provided to GM for Dexos approval and some vendors do not want to provide the oil formulation details to protect their products. If anyone is interested in more info, PM me for details.

And about the engines being "Cold Tested", I am pretty sure this is not being skipped, "Cold Testing" shows no level of combustion because no fuel is introduced into the engine. There would be no real benefit for skipping "Cold Testing" because this limits feedback for problems during quality control.

Most modern engines need less "Break In" period, especially with piston rings. Gone are the days of harder piston ring materials and todays engines have matched cylinder hone surface to seat softer piston ring materials in a quicker fashion. Same with camshaft and lifters now that roller lifters are more the standard. Break in has more to do with bearings, transmissions and differentials, not putting undue loading on these components for 500-1000 miles or so. Most normal driving will be fine for the first 500-1000 miles, whether you are in town or on the highway. Refrain from towing and hauling heavier loads would be wise as well.