Just picked up my new 2011 Mustang GT. The manual says to vary the speed for the first 100 miles in order for the engine to break in. Anyone heard any differnt?

 

I'm surprised they say that much. Todays engines are track-ready off the showroom floor.

Yes, vary your speed. I think a few 0-100 MPH at WOT should do the trick. Save the runs past 140 MPH for AFTER that first 100 miles.

 

Yea, I was told there was really not a break in period for these engines. The dealership told me to drive it like I stole it if I wanted.

 

Your car is all new. New engine, new axle gears, new tranny gears. All need internal parts to be "worn in" to each other. This generates extra heat over and above what normal driving fully broken in creates.

Varying your speed (and engine rpm) helps ensure that oil and various lubes splash everywhere inside to help keep the parts in there from locally overheating. Sustained constant speed driving will not do this, you probably shouldn't trust your $30+k purchase to "luck of the draw".

How long you choose to do your break-in and how fast you drive during that time is between you, whatever is in your owner's manual, and your conscience. But only 100 miles is a pretty minimal number. Patience.


Norm

 

Look for their agenda.

1. It's not their car any more.

2. The shop contributes to dealership profit.

3. They might get to sell you another car, sooner.


Norm

 

I haven't had a single issue with the car yet, and I never worried about break in. The only thing I did was kept it under 100mph.

 

my order got "randomly selected" and pulled off the assembly line for road testing and quality assurance. my car came with 77 miles on it... good thing or bad thing?

 

If you ordered it that would **** me off. I doubt it is a bad thing simply because of the mileage. I bought mine off the lot with only 7 miles on it. There is just something nice about all the miles being my miles.

 

If you go by the OM, then you only had 23 miles to go and you're done the break-in. I'm sure whatever those 77 miles were did no harm. If anything, they may have fixed a couple of issues that would save you a trip in for warranty work. Either that or quality assurance is another term for Bubba needing a ride for his date...

 

I didn't push my car to 100 until I had over 1000 miles on it.

You really dont have to, but if you are as cautious as me, you can do a break-in period for up to 2000 miles. Again, that is not necessary.

Also, even though you don't have to, I would suggest you change the oil at around 2000-3000 miles. I did so in my car to take out any possible shards that might might have resulted from manufacturing and also from the break-in time.