Engine Break in Procedure

[Crmaverick]

I hear a lot of different opinions on this, after 60 miles the factory recommends brief wide open throttle.

How come I hear people saying to stay under 4,000 rpms? When you put the hammer down for two or three seconds at a cruise you’re going over 4K rpms when the tranny down shifts, but this is what the factory recommends. Just wondering the reasoning why people are saying no going over 4K rpms?

I did 80 miles of back roads under 4K rpms, now I’m doing 50-60 mph plus brief wide open throttle at cruise and reving into the 5k range. Not sure how it would be possible to do wide open under 4K unless you have a manual

Sponsored

 

[Klutch]

You will get as many opinions on this as you would asking about the best engine oil... Or the best religion.

 

[TheITGuy]

IMHO your best bet is to follow the instructions in the manual. Modern engines don't require the prolonged and/or complex break-in procedures that used to be required.

Also, check out this thread.

 

[Bowerss2]

You will get as many opinions on this as you would asking about the best engine oil... Or the best religion.

/This

So I will throw my wrench into the ring. There is zero point to babying an engine when new, if its going to be a victim of crib death, there is no amount of babying that will stop that. Also there are reasons to run an engine hard during break in that have to do with rings, cross hatching, seating and blah blah blah… Basically with new built engines I do about 3-5 50% pulls, followed by 3-5 75%, and 5 or more 100% pulls then change the oil and your done.

On the stand I usually warm the engine up, making sure to not let the RPM rest, and to get the initial tune OK, then run at WOT for 5 min against the rev limiter (to keep the rpms high, but varying) Check the Air-fuel is OK. After 5 min, drain the oil, and done.

With a factory built engine... meh, I bet it really doesn't matter all that much, they have already been run before you got them, and I bet my shirt they keep that line in the manual about break in because if its not in there people will bug the dealers about it.

Basically I wouldn't worry about It, beyond not letting it idle too long when new, and trying to keep the RPM varying for the first few hundred miles.

 

[Crmaverick]

/This

So I will throw my wrench into the ring. There is zero point to babying an engine when new, if its going to be a victim of crib death, there is no amount of babying that will stop that. Also there are reasons to run an engine hard during break in that have to do with rings, cross hatching, seating and blah blah blah… Basically with new built engines I do about 3-5 50% pulls, followed by 3-5 75%, and 5 or more 100% pulls then change the oil and your done.

On the stand I usually warm the engine up, making sure to not let the RPM rest, and to get the initial tune OK, then run at WOT for 5 min against the rev limiter (to keep the rpms high, but varying) Check the Air-fuel is OK. After 5 min, drain the oil, and done.

With a factory built engine... meh, I bet it really doesn't matter all that much, they have already been run before you got them, and I bet my shirt they keep that line in the manual about break in because if its not in there people will bug the dealers about it.

Basically I wouldn't worry about It, beyond not letting it idle too long when new, and trying to keep the RPM varying for the first few hundred miles.

yeah that makes sense, I did about 70 miles back hilly roads, varying rpms. Then between 80 miles and 300 miles I did 10 WOT pulls from 40Mph to about 55 or 60 mph. I also used manual mode about half the time to down shift for some engine braking.

 

[Bbannongmu]

I babied it for 700 miles or so and then...

 

[Rick Behrendt]

I just bought my Sport S and the service manager told me that the computer needs to learn how you drive so he said to "drive it like you stole it" and no cruise control for the first 500 miles, if not then you will notice a sluggishness and the tranny(auto) will learn to shift at the wrong time. The fix for this is to take it in and have it recalibrated at the dealer.

 

[Rick Behrendt]

Oops, I meant reprogram not recalibrate

 

[velogeek]

Yeah that service manager is full of shit. Just drive it like normal. The shift points are good and will adjust slightly and it's already programmed for some pretty firm shifts off the lot.

Driving like you stole it, unless you intend to keep driving it that way, isn't going to do anything if your usual is more timid. The learning process is ongoing, not some limited-term program.

 

[Rick Behrendt]

obviously what my service manager meant was not to baby it, and I would certainly listen to him, someone that services and works on them 5 days a week and has been to all the certified schools and works for the largest FCA dealership in the world over somebody else.

 

[Mr._Bill]

obviously what my service manager meant was not to baby it, and I would certainly listen to him, someone that services and works on them 5 days a week and has been to all the certified schools and works for the largest FCA dealership in the world over somebody else.

I would tend to agree, as long as his advice doesn't go against what is written in the Owner's Manual. All the training in the world means little if the trainee is handing out advice that contradicts information provided by the trainer. Any documentation provided by FCA supersedes what the dealer may say, especially when it comes to warranty related issues.

 

[velogeek]

obviously what my service manager meant was not to baby it, and I would certainly listen to him, someone that services and works on them 5 days a week and has been to all the certified schools and works for the largest FCA dealership in the world over somebody else.

Yeah... I used to wrench at a Jeep dealership... I don't trust Service Managers as far as I can throw them because they are hired as the front line to protect the dealership, not provide any authority on a vehicle. My service manager and the service director at the jeep dealer literally could not explain the process of changing oil let alone do it. I had similar experience at Toyota and Ford.

The reality is that you are right - don't baby it - but at the same time, don't romp it either. For the first 500 it's good to vary the engine speed while cruising and occasionally give it a few harder (~3/4 throttle) pulls up to speed but you really want to give it a chance to settle in under normal operating conditions before you start hammering on it or go towing 6k.

 

[Crmaverick]

I followed the manual and did 70 miles normal driving back hilly country roads varying speeds. Then from 70-500 miles I did roads up to 60 mph max and varying speed/rpm and about ten 40-60mph WOT pulls.

She’s broken in now at 2,000 miles I’m now seeing 23 MPG on this thing, running Shell 87 octane. Jeep is a Max tow with 4.10 gears.

 

[bangolia]

I have a 150 mile drive home on the interstate. How am I supposed to drive under 60?

 

[velogeek]

I have a 150 mile drive home on the interstate. How am I supposed to drive under 60?

You don't and don't need to. Just don't settle in on cruse and vary your speed a bit. Even being in light traffic that varies your speed 5mph on hills is enough variance - you just want to mix up the engine load where you can.

Being anal about break-in is like trying to eek that last 5% out of the maximum engine life - how you treat the engine (e.g. not going WOT everywhere you go or towing 90% of the time) and your maintenance habits are going to make up the other 95% so long as that break-in isn't abusive.

Sponsored