Break in period oopsie.

[NXTGENAutomotive]

There’s no such thing as a break in anymore. The materials used now are different than the old rings and camshafts from the 60s. I did burnouts right off the showroom floor.

Not 100% true, but true for most vehicles.

Our shop M4 was purchased brand new and it came with a special break-in oil in both the engine and the differentials, it’s AWD so front and rear.

Beyond the few BMW M cars, Porsches and some other performance vehicles still do come with break-in oil and require break-in service within the first thousand miles.

With vehicles like that, you would be better off not getting too crazy. With our M4, I was honestly more concerned about the differentials than the S58 engine, but none those of those break in oils are meant for getting wild or going more than 1500 to 2,000 miles max.

New Corvettes, and some others have software that limits how high you can rev them for a certain amount of miles and then you can give them the beans.

With most vehicles like your Jeep, the initial break in period is really just making sure that the Pistons and rings are seating or seated properly.

it really only takes a few heat cycles to do this, so if it had 40 miles on the clock, those were probably even more important than the miles you drove it home. That’s why they say to vary the engine speed, though, you’re really just making sure that those seat well. After a few heat cycles they should be good.

The more you vary the engine during those initial heat cycles, the better it can get the full scope and seat fully. That’s also why the worst thing you can do is take a brand new car on the highway, and set the cruise control or drive the same speed for a long period of time. You really want to cycle those through a bunch of different speeds and heats for the best results.

In that regard it would be better to stomp it a bit, but not beat on it, vs purely baby it or do steady hwy.

The best break in is a little bit of everything. Slow, fast, stomp it.

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[Supazuk]

You have 36 months or 36,000 miles to break it.

Quit wasting time.

I laugh at that 36k in 3 years, is that even using it? I put 25 k in the last 10 months !

 

[Greg_L]

The reason you "broke in" older engines was for camshaft lobes/lifters and piston rings.

Those aren't issues anymore. Cams are quite different now, oil is different, and rings/cylinder honing is done to perfect finishes. Cam lobes and lifters was the main thing. Rings seated in pretty quick with a little heat. First run-in and heat cycle and those things were handled. No reason to baby it for 500-5000 miles or whatever people think. If those things are gonna fail they would have failed already. I've seen many cam lobes go bye-bye within 15 minutes.

The only thing you probably should do is dump that break-in oil and filter before 5k miles.

 

[RHINO79]

I'd worry more about the test drives of the first 41 miles, some take them out and pound the snot out of them.

 

[Catahoula7]

Well look in the high performance world. The last LS I built for my Tahoe PPV. Head, cam, complete valve train, Intake, injectors and 3200 stall converter........warmed up for initial base map.......then ripping it on the dyno at WOT for about 10 runs to dial the tune and about another 5 for the full trans tune.

Break in is a myth.......except for clutches (MT)

I have heard some abuse stories from builders I know, though tbh, I would trust a built LS3 a whole hell of a lot more than a pentastar. You can sell the Trans-Am mullet guy a jeep, but you can't take the LS cult out of him. lol.

I have been driving more, keeping it under 4k until I hit 50 and then manually shifting around before doing short full throttle pulls from 50. That seems to be what the instructions are.

Do you think those 1st 41 miles were treated with breakin period in mind? I wouldn't sweat it. Enjoy it!

I did some of those, and I was decently gentle, lol. Fingers crossed.

You’re completely fine. Just don’t hammer on it for the first 500 miles and you’re good. Funny thing about my 3.6l is I was never hard on it till like 7k miles when I wailed on it for like 20 miles trying to keep up with a friend on some mtn roads. I was in manual mode and it was 4-6k RPM wide open for the whole time. It started getting a lot better mpg after that. I was annoyed that it never came close to the EPA figures and then after that it started getting EPA figures. Actually, slightly better. It’ll get 22-23 mpg on the hwy going 75 mph on 285/70/18s. It came with 255s and I still have the stock 3.73s. It used to only get 18-19 mpg hwy. It’s been like that for years now. It’s a 2020.

Not 100% true, but true for most vehicles.

Our shop M4 was purchased brand new and it came with a special break-in oil in both the engine and the differentials, it’s AWD so front and rear.

Beyond the few BMW M cars, Porsches and some other performance vehicles still do come with break-in oil and require break-in service within the first thousand miles.

With vehicles like that, you would be better off not getting too crazy. With our M4, I was honestly more concerned about the differentials than the S58 engine, but none those of those break in oils are meant for getting wild or going more than 1500 to 2,000 miles max.

New Corvettes, and some others have software that limits how high you can rev them for a certain amount of miles and then you can give them the beans.

With most vehicles like your Jeep, the initial break in period is really just making sure that the Pistons and rings are seating or seated properly.

it really only takes a few heat cycles to do this, so if it had 40 miles on the clock, those were probably even more important than the miles you drove it home. That’s why they say to vary the engine speed, though, you’re really just making sure that those seat well. After a few heat cycles they should be good.

The more you vary the engine during those initial heat cycles, the better it can get the full scope and seat fully. That’s also why the worst thing you can do is take a brand new car on the highway, and set the cruise control or drive the same speed for a long period of time. You really want to cycle those through a bunch of different speeds and heats for the best results.

In that regard it would be better to stomp it a bit, but not beat on it, vs purely baby it or do steady hwy.

The best break in is a little bit of everything. Slow, fast, stomp it.

I have been keeping it under 4k while I get up to 50, manually shifting around and slowly surging speed up and down, cruising between 50-55, while doing occasional full throttle pulls from 50-70ish. That is kind of what I got out of the instructions in the manual, but they are so vague.

The reason you "broke in" older engines was for camshaft lobes/lifters and piston rings.

Those aren't issues anymore. Cams are quite different now, oil is different, and rings/cylinder honing is done to perfect finishes. Cam lobes and lifters was the main thing. Rings seated in pretty quick with a little heat. First run-in and heat cycle and those things were handled. No reason to baby it for 500-5000 miles or whatever people think. If those things are gonna fail they would have failed already. I've seen many cam lobes go bye-bye within 15 minutes.

The only thing you probably should do is dump that break-in oil and filter before 5k miles.

I have been meaning to look up lube schedules for the gladiator. Is 5k enough? I have heard 1000-2000 for first fluid rotation.

I'd worry more about the test drives of the first 41 miles, some take them out and pound the snot out of them.

I was about 10-20 of those. I gently pushed it to 60 to feel if the rubicon was really that abusing on highways before buying. I decided the internet was full of babies and the ride was what I expected out of a truck, so I bought it.

 

[loganjeeps]

There’s no such thing as a break in anymore. The materials used now are different than the old rings and camshafts from the 60s. I did burnouts right off the showroom floor.

Agree, drive it the way that makes you happy at 5miles or 5000miles.

I will say as its been noted before on other threads, your MPG will take some time to settle in. I thought i was doing something wrong on my 2022 but it eventually got to where it was expected. replaying the same observation now on my 2024.

 

[Solar Sparky]

Break it in like you are going to use it. I was at the top of Argentine pass before 300 miles.

 

[Jefe1018]

There are things to worry about, I don't think this is one of those things. I always wondered about those motors that are purchased with like 70-80 miles on them that have been test driven.. has anyone not floored a car on a test drive for at least short bits?

 

[chr15m]

All personal opinions aside, it's in the manual.. doesn't sound like the OP violated any recommendations in the manual. For others, no, low gear full throttle is not recommended and advised against explicitly. Full throttle from higher gears though, is recommended, so the details matter, at least in regard to OE recommendations.

It's your vehicle though, everyone drives theirs differently so I'm sure break in is a fairly forgiving period as long as you're reasonable.

Also, no recommendations for early oil changes, rather to follow the same guidelines as all other oil changes. I have no doubt that'll remain a widely contested thing.

I personally drive it casually for the first 500ish miles and gave it a couple good highway pulls after reaching temp. The truck has treated me well, not burning any oil and can easily get 18-20mpg in the summer on 35s.

Enjoy the truck

 

[Janster]

Our shop M4 was purchased brand new and it came with a special break-in oil in both the engine and the differentials, it’s AWD so front and rear.

Beyond the few BMW M cars, Porsches and some other performance vehicles still do come with break-in oil and require break-in service within the first thousand miles.

My husband has a 2025 M4……. The breakin period is 1,200 miles. When you reach that mileage…..you are required to take it in for the Break-in Service (part of the warranty). Up to that point - BMW limits the horsepower (I believe - but we never tested that out). During the breakin service, they’re looking for any signs of wear & abnormalities. After you get that Break-in Service done - they remove those horsepower limitations. High end performance, high end tolerances, high end skilled technicians, etc. BMW doesn’t want you to come back in for warranty repairs.

 

[Catahoula7]

My biggest concern was the fact I hit 90 in the first 100 miles, and probably spent 30 minutes over 55. I did not beat on it, but I had some passing pulls at probably 60 percent throttle. Since then I have mostly followed the instructions. I also idled for maybe 20ish minutes at the dealership trying to get my phone back on, which is a no-no I have heard.

I am pretty anal about warming engines before abuse because I still have an LS powered Trans-Am and the aluminum block does not expand as fast as the rods and pistons.

All personal opinions aside, it's in the manual.. doesn't sound like the OP violated any recommendations in the manual. For others, no, low gear full throttle is not recommended and advised against explicitly. Full throttle from higher gears though, is recommended, so the details matter, at least in regard to OE recommendations.

It's your vehicle though, everyone drives theirs differently so I'm sure break in is a fairly forgiving period as long as you're reasonable.

Also, no recommendations for early oil changes, rather to follow the same guidelines as all other oil changes. I have no doubt that'll remain a widely contested thing.

I personally drive it casually for the first 500ish miles and gave it a couple good highway pulls after reaching temp. The truck has treated me well, not burning any oil and can easily get 18-20mpg in the summer on 35s.

Enjoy the truck

 

[chr15m]

My biggest concern was the fact I hit 90 in the first 100 miles, and probably spent 30 minutes over 55. I did not beat on it, but I had some passing pulls at probably 60 percent throttle. Since then I have mostly followed the instructions. I also idled for maybe 20ish minutes at the dealership trying to get my phone back on, which is a no-no I have heard.

I am pretty anal about warming engines before abuse because I still have an LS powered Trans-Am and the aluminum block does to expand as fast as the rods and pistons.

In regard to the motor itself, 90 is not really the concern. Perhaps on other moving components , but the transmission will make that 90 the same as doing 35 with more throttle input.

Long idles, not 20 minutes, are not ideal just because they can result in improper detonation, but I'm guessing you didn't end up with any CELs. Good idea not to make a habit of it, yet many do without issue. In my experience that is a concern for work site guys, running idles for hours.

I'm just going to be concise with it, your truck is fine, the pulls were probably more beneficial that harmful, the idling certainly did no permanent harm and the speeds aren't anything I'd lose sleep over.

Just try not to do any stoplight WOTs until you have more time on the clock and the oil is hot.

 

[Pilsner]

There’s no such thing as a break in anymore. The materials used now are different than the old rings and camshafts from the 60s. I did burnouts right off the showroom floor.

There absolutely is. Gears still need break-in.

 

[NXTGENAutomotive]

My husband has a 2025 M4……. The breakin period is 1,200 miles. When you reach that mileage…..you are required to take it in for the Break-in Service (part of the warranty). Up to that point - BMW limits the horsepower (I believe - but we never tested that out). During the breakin service, they’re looking for any signs of wear & abnormalities. After you get that Break-in Service done - they remove those horsepower limitations. High end performance, high end tolerances, high end skilled technicians, etc. BMW doesn’t want you to come back in for warranty repairs.

Not really applicable to current Jeep models but wanted to share examples of some current makes and models that still have pretty stringent break-in procedures.

In the current G8x generation it is actually a big misconception, even among many service advisors that BMW limits power. We make custom tunes for most BMW models with locked engine control units, and that is absolutely false.

Not using the full power is up to the driver to have self control and it’s not easy with new M4s .

what the manual prescribes for the break-in service is no less than 900 miles and no more than 2,000, with the ideal place being at 1,200.

When the car is cold, every start, even beyond the break in time. The digital tachometer lowers the red line to near 4000 RPM, and it progressively goes up to the 7100 RPM limit once the engine is fully warm. Again, not a real limit but a suggestion.

But that’s a good tip for everyone, make sure the car is fully warmed up before you really step on it

 

[Camaroboi13]

There absolutely is. Gears still need break-in.

My break in period went like this

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