Engine Break-in

There is nothing wrong with driving it slow or hitting the rev limiter. Just vary the RPMs as much as you can.

The two things you do want to avoid is sustained (more than 3-4 consecutive minutes above 4500rpm (the oil heats/engine heats up exponentially doing this) or staying over 6000rpm for more than 5-6 second bursts.

Also dont fall for the "change your oil" after the first 1,000 miles hype. It is not needed and may actually harm the car (assuming the rumors about the break in additive were true). I am waiting till i hit around 7,500 to change mine for the first time and parying it doesnt start ticking when i do.

The salesman said to me "let's take it for a spin to make sure it's ok, I haven't been in one yet".

Pulled out of the lot and saw 6500 rpm, chirped 2nd on the shift. Did it again at another stop sign. We both couldn't stop smiling.

On the way home, many WOT in 3rd and 4th and let it decelerate.

Seating the rings is important, which I was trying to do. Sustained high rpm, steady rpm or lugging the motor is bad for break-in.

Only have about 500 miles on my car in a year (5/10 build and have other DD's), but no oil consumption and I drive it the same each time it is out.

What's "normally" mean? :hihi:

The manual says there is no break-in period but then right below that they say no trailer towing (no worries) and no high performance driving (I take that to mean actual racing so I guess I'm okay there too) in the first 1,000 and try to vary your speed for the first x miles. I forget what x miles was now but I tried to be a good boy and not use the cruise in the beginning.

I'm just past 1,000 miles now and I've used a little oil but nothing drastic.

My dealer recommended 5,000 oil change intervals for a GT and that makes sense to me. I wouldn't go 10K on a 4 cylinder Honda so I'm sure as hell not going to stretch it to 10K on a high performance car like this Mustang. Oil changes are cheap, trying to save $30 bucks to go that long between oil changes on a $35K investment is just stupid math.

412horses said:

What's "normally" mean? :hihi:

The manual says there is no break-in period but then right below that they say no trailer towing (no worries) and no high performance driving (I take that to mean actual racing so I guess I'm okay there too) in the first 1,000 and try to vary your speed for the first x miles. I forget what x miles was now but I tried to be a good boy and not use the cruise in the beginning.

I'm just past 1,000 miles now and I've used a little oil but nothing drastic.

My dealer recommended 5,000 oil change intervals for a GT and that makes sense to me. I wouldn't go 10K on a 4 cylinder Honda so I'm sure as hell not going to stretch it to 10K on a high performance car like this Mustang. Oil changes are cheap, trying to save $30 bucks to go that long between oil changes on a $35K investment is just stupid math.

Click to expand...

Thats because the oil in that 4cy honda accord has almost no resovoir and thus..CONSTANTLY circulates in the engine and stays pretty much the SAME temperature as the engine temp 100% of the time. And THAT..in a car that is over 3,000rpm on the highway at speed...requires an every 3k oil change interval. Not so in the mustang where the oil spends a significant amount of time in the sump and combine with the piston cooling oil jets...the over all temp of the oil stays much lower than in that 4cy Honda. (unless you are sustained over 4,500rmps), and that more than triples its life span. (Combine that with the fact that your 8cy mustang can sustain freeway travel at less than 2,000rpms and spends much less time above 3,000rpms than that honda accord in normal city driving stop and go driving due to how much power the 5.0 has)

With the 8qt deep sump and oil cooling jets, changing it at 5,000 miles would be the same thing as changing it on that honda Accord every 1,500 miles, unless you are driving more than 3-4 min at a time above 4,500rpms or more thatn 10 second bursts near redline.

Now, its your car, if you want to change out brand new oil have at it yourself. I agree that 10,000 is out of my comfort zone (for now) so i have settled on the dealer recommended 7,500 interval. That way even if i drive it hard once in a while i am still 25% early on the factory recommended interval.

I think 5,000 intervals is ideal for anyone who lives in the mountains, tracks or drags or just abuses the car though.

PS. Thats the thing about synthetic oil. Its not that its a better quality oil (its not..in fact i think it is inferior if you compare brand new synthetic to brand new petroleum), its that it is more heat resistant and thus, over time maintains viscosity when petroleum based oil thins. Personally i would rather use the better quality oil and change it more frequently (based on my driving habits) but i do think the synthetics can go 10k miles in this car safely...as can the recommended Ford Motorcraft synthetic blend (which is what i use).

Lastly i think if you do highway driving you are safe at 10k because with highway driving, you can put 10,000 miles on a car in 1/2 to 1/3 the hours of operation on the engine that it would take to put even 7,500 miles on a car that is primarily driven in the city.