4xe break-in process

bkinnj

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So as we all sit here patiently waiting for our glorious 4xe's to start shipping, I'm wondering if there needs to be any modifications to the suggested break-in procedure? I looked through the 4xe supplement and there is nothing mentioned that I saw. So then I reverted to the 2021 JLU owners manual; see below in red for excerpt.

Seems that will cover the ICE and rest of the mechanical powertrain but should we be doing anything specific for the high voltage system?


ENGINE BREAK-IN RECOMMENDATIONS — GASOLINE ENGINE (IF EQUIPPED)

A long break-in period is not required for the engine and drivetrain (transmission and axle) in your vehicle. Drive moderately during the first 300 miles (500 km). After the initial 60 miles (100 km), speeds up to 50 or 55 mph (80 or 90 km/h) are desirable.

While cruising, brief full-throttle acceleration within the limits of local traffic laws contributes to a good break-in. Wide-open throttle acceleration in low gear can be detrimental and should be avoided.
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Jamie Brown

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Well, when I pick up mine I will be driving 1/2 mile from the dealer lot to the interstate then it will be 75mph for a good 3hrs to my house. That should be more than enough break-in time.
 
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bkinnj

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Jamie Brown

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cutandrun

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ENGINE BREAK-IN RECOMMENDATIONS — GASOLINE ENGINE (IF EQUIPPED)

A long break-in period is not required for the engine and drivetrain (transmission and axle) in your vehicle. Drive moderately during the first 300 miles (500 km). After the initial 60 miles (100 km), speeds up to 50 or 55 mph (80 or 90 km/h) are desirable.

While cruising, brief full-throttle acceleration within the limits of local traffic laws contributes to a good break-in. Wide-open throttle acceleration in low gear can be detrimental and should be avoided.
So full-throttle is good, but wide-open throttle is bad??? I can’t even remember how many threads I’ve read on “baby it” vs. “drive it like you stole it” break-in advice. Both sides make what seem to be common sense arguments for their case. The only thing that sort of makes sense to me on the 4xe is to break in the engine sooner rather than later. I won’t be going everywhere on electric until the gas engine has had a chance to run a bit. No evidence to support my case. Just feels right.
 

Windshieldfarmer

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Nothing complicated- just make sure you vary the RPMs if driving on the highway...the hybrid system shouldn’t need any break in other than not driving the h out of it off the lot.... I personally like to complete the first oil change at 2,000 miles then every 6,000 miles thereafter.
 

Roverhi

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Not holding a steady rpm for long periods of time has been the secret to a successful break-in is what I was taught. Hard acceleration but not all the way to rev. limit occasionally is good but don't do tire burning peel outs or other maximum stress antics on the drive train. freeway cruise control at a constant speed is not ideal. If you have to go on the freeway vary the speed on a regular basis but best to stick with backroad and/or city driving where you are forced to vary the rpm/load regime. You want the engine to see a variety of rpm/load scenarios without stressing things to the breaking point.

Manufacturing tolerances are way better than they used to be so strict break in protocol is not as critical as it used to be.
 

Demonic

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FCA executives went to their top engineers and said:
"Listen guys, this is important. We want you to design an engine that we're going to mass produce and warranty, BUT here's the important part - we only want it to last if people on the internet forums figure out the secret to breaking it in. Do you think you can do that?"
And the engineers respond: "Think we can? We've been waiting for this moment our whole lives. Good luck internet people."

But joking aside, just don't let it idle for hours on end, and don't abuse it.
 
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DavidArmen

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FCA executives went to their top engineers and said:
"Listen guys, this is important. We want you to design an engine that we're going to mass produce and warranty, BUT here's the important part - we only want it to last if people on the internet forums figure out the secret to breaking it in. Do you think you can do that?"
And the engineers respond: "Think we can? We've been waiting for this moment our whole lives. Good luck internet people."

But joking aside, just don't let it idle for hours on end, and don't abuse it.
In terms of not letting it idle for hours, is that just during the break in period or just in general?
 

Demonic

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In terms of not letting it idle for hours, is that just during the break in period or just in general?
Ideally in general. When the engine is idling especially after a cold start it's a richer mixture which creates a dirtier burn. That's why you sometimes hear that letting a car "warm up" actually isn't any better on the engine. When you see guys mention highway speeds with varying RPM's, the idea was that at higher RPM's and with varying loads the piston rings would start to seat to the shape of the cylinder liner. On hand built race engines sure, but I doubt you'll find much evidence that this matters on a modern production engine. Usually car forums will just be filled with anecdotal confirmation bias - "I did xy break-in on my two cars, and they lasted over 200k miles, so that's how I know my method is best."

My M3 was driven like a Granny for most of it's life. I thought I was being good to it. At 25k miles I had the cylinder heads pulled to put a stronger gasket in for the supercharger, and the machine shop said they were surprised by how much fouling they had to clean and asked if the car had ever even seen redline. It hadn't lol.
 

Dryver

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Full throttle is "flooring it"

Wide open throttle is "pedal to the metal"

Hopefully, that clarifies it.
And if that doesn't, then full throttle is accelerating as quickly as possible to a given speed and open throttle is continuing to accelerate and then
maintaining max speed possible.
 

oldcjguy

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So what exactly is the difference between “full throttle” and “wide open throttle?” 🤔
The warning if against "wide open throttle in low gear". No difference between full throttle and wide open throttle. They are saying full throttle in upper gears is fine, like when you are passing someone on a highway not doing 130mph LOL
 

eLECTRICON

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Oh Im gona break it in all right!! I'm going strait to Moab in April for a week. I've got parts in the garage just waiting for the transformation. I custom made rears spring to swap with the springs on my 3.5" Teraflex lift to handle the weight of the battery pack for now. When Teraflex has them, ill get the 4xe springs from them. Falcon aDapt shocks. 35" Falken MTs. AND some beautiful custom body parts!!!
 
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