Break-in period, who follows it?

Chemy350

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In my previous job, I was an A&P Mechanic, basically airplane mechanic. I know engines and the reason for break in periods... of previous generations. In today's cars, engines are produced with MUCH tighter tolerances than they were 20 years ago and beyond. THey no longer need to seat the rings for thousands of miles or break in the seals on the valves etc. They fit nearly perfect from the factory in today's moderns engines, transmissions etc.

The only break in period I follow is 2 rules. 1 - Make sure the oil temperature is up to around 200 degrees, usually takes about 10-15 min of driving to get there. Once thats warm, drive it as hard as you want, floor it, no problem. and 2 - never set cruise control for the first 500 miles. If you want to take a road trip, you want to change the speed at which your driving constantly, varying the RPMS.

I have done these two rules for about the past 20 years, I have literally never had a single engine problem in any vehicle I have owned, that I purchased new.

I understand everyone has their own opinion, this is just mine.





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Paluss

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If I’m going to spend 50k on a vehicle I’m going to follow the engineers’ recommendations on how to break it in. Same as I do on differential rebuilds. Common sense.
I agree, common sense, I never heard anyone complain "I wish I had not followed the recommended break-in procedures"
 

Texan42

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In my previous job, I was an A&P Mechanic, basically airplane mechanic. I know engines and the reason for break in periods... of previous generations. In today's cars, engines are produced with MUCH tighter tolerances than they were 20 years ago and beyond. THey no longer need to seat the rings for thousands of miles or break in the seals on the valves etc. They fit nearly perfect from the factory in today's moderns engines, transmissions etc.

The only break in period I follow is 2 rules. 1 - Make sure the oil temperature is up to around 200 degrees, usually takes about 10-15 min of driving to get there. Once thats warm, drive it as hard as you want, floor it, no problem. and 2 - never set cruise control for the first 500 miles. If you want to take a road trip, you want to change the speed at which your driving constantly, varying the RPMS.

I have done these two rules for about the past 20 years, I have literally never had a single engine problem in any vehicle I have owned, that I purchased new.

I understand everyone has their own opinion, this is just mine.
What is the reasoning for varying the RPMs and not using cruise control? I drove home from the dealership for 4 hours of 90% interstate, I tried to vary as much as I could but stayed in 8th gear most of the time. Was too hard to vary while going 65 mph with traffic.
 

offset_98

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I had to drive mine 500 miles right off the lot to get it home. It was all freeway and I used cruise control for some of it.

My Toyota I had to drive 2000 miles off the lot to get it home and I used the cruise on it too.

Both are fine, the toyota has 160k on it and still running strong.
 

Melny67

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I just didnt floor it as much feather the throttle that should be enough. Did that for about a month
 

VooDoo1

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I followed the recommended procedure, since I purchased it and plan on keeping it for a long time. It makes me feel better. Kind of like preventative maintenance.

Now, if this was a lease to be returned in 3 years, I would have drove it like I stole it right off the lot.
 

entropy

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I didnt. To be honest, I didn't know this was a thing. The JL was the first new vehicle I've ever bought, I was under 30 when I bought it so wth did I know, and nobody told me, all the dealer cares is to make the sale, in fact they probably don't even know either. I don't push the engine, so hopefully I didn't break anything lol.

Another confession, I didn't know you could finance a car purchase without getting ripped by the stealership, didn't know you could go to a credit union and get a sweet rate. So I bought it outright cash. Could have easily financed a rubicon instead with a massive down payment. You live and you learn! at least I own my jeep.

Oh and we millenials have this habit of not reading manuals.
 

zakaron

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I've never owned a brand new vehicle, so I figured it was best to at least follow the user manual as closely as I could. Things I did during the first 300 miles:
- kept revs under 4K
- varied revs and load during driving (ie, no cruise for 2hrs straight)
- gave a few heavy and WOT runs between 3K-4K (all after warmed up to operating temps)
- tried to keep speed under 65 so as not to overheat diff gears

No idea if any of this will help its longevity. Chances are rings may have already been seated by factory run-in. But at least it gave me peace of mind while I familiarized myself with its driving characteristics and behavoir.
 

VNT

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I followed Mototune USA procedure to seat the rings, get oil up to temp, then do half dozen hard pulls on back roads and lift off throttle, will ensure good ring sealing. Do this during first 25 miles when engine is brand new, ie pick up Jeep from dealer and do his method. With the shitty low tension rings they use now on the engines, too many oil burners from all makes.

Then drive on back roads varying RPM, dump oil at 100, 1000, 2000. Then normal oil changes with good synthetic. That is my method.


http://www.mototuneusa.com/break_in_secrets.htm
 

swish77

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Just picked up my 2021 Wrangler Sport S (2-door) ... and my salesman and service manager insisted there is no longer a break-in period for Jeeps. I pointed out the section in the owner's manual about the break-in, and the response was that it's still unnecessary regardless of what's in the manual. Very odd and confusing. I'm being careful anyway.
 

JeepFan

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Just picked up my 2021 Wrangler Sport S (2-door) ... and my salesman and service manager insisted there is no longer a break-in period for Jeeps. I pointed out the section in the owner's manual about the break-in, and the response was that it's still unnecessary regardless of what's in the manual. Very odd and confusing. I'm being careful anyway.
I believe that the engineers who designed your Jeep know much more about it than the people at your dealership. I certainly plan to follow the instructions in the Owner's Manual when I get mine.
 

oldcjguy

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The owners manual procedure hasn't changed in MANY years. I think the 55mph speed limit goes all the way back to the 70's and 80's when that was the national speed limit. We also now have up to 8 speed transmissions with 2 overdrives and a range of rear gear ratios. Not a one size fits all. The engineers that designed the engines didn't write the break-in procedures. Oddly enough it's the same written break-in procedure for a 2.0T, 3.6, 5.7, 6.4.... Hmmmm

The key to any break-in is varying loads and varying speeds (engine and jeep). It's not just the engine you're breaking in. As a matter of fact most modern engines require very little "break-in". Low tension rings, exotic materials, roller cams, blah blah blah. Transmission and axle gearing break-in is still a thing though. Avoid long constant speeds and loads (no cruise control), and long highway trips for a little while. Best way to break in a vehicle is city/rural driving with varying loads and varying speeds. Plenty of heating and cooling cycles.
 

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