New car engine break-in, still relevant?


#1

I’m planning on buying a new 2015 mitsubishi mirage. I’ve read that most manufacters break in the engines during production and it is no longer neccessary for the owner to do it.

My first drive will be from dc to wv, about 80miles. The route has tons of hills and speeds of about 70-80mph. The engine will probably hit 5000rpm on some of the hills. Is the breakin neccessary and if so, what is the proper procedure?


#2

First check the owners manual and follow the instructions there. You really want to gently drive the car for at least a few hundred miles and vary the speed so you are not driving at a constant speed. Otherwise you don’t need to do anything special. But 5000 rpm is a little extreme!! Why would you find it necessary to run an engine at that level? What you wanna go 50 mph up a hill in first gear? So I’d reconsider that. No need to wind it out that much.


#3

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

It’s very controversial, and I’m sure some will balk at it, but I’ve done it on all my vehicles (bikes, cars and truck), and with almost 500K between them, they all run great, blow no smoke, and use no oil.

My 4Runner was treated like the link from new. It’s at 235K now, and running fantastic. Last check (about 35K ago), compression was the same as it was at 30K. I also drive it “like I stole it” on a regular basis. Never had the engine open (for anything), regular services, zero failures.


#4

I agree with Bing, no need to run the RPMs up to 5k except in an emergency.


#5

Yeah one of the roads you’re going downhill and then immediately it turns into a steep climb for a couple of miles. I maintain the same speed from the momentum, so in my current corolla…the engine hits 3000rpm at 75mph. I figured a smaller 3 cylinder would hit somewhere around 5000rpm to maintain the same speed.


#6

Yeah, that is only a 1.2 L 78 HP engine. What does the owner’s manual say re break-in?


#7

The thing about cars is that they are supposed to serve us. If you can’t do nice, happy, gentle drives it’s OK. Nothing bad will happen. The reason for break in is that the new car is still a bit stiff and is a little harder to move. If you aren’t carrying four people and a full trunk, the car is still having an easy day.


#8

The owner’s manual will tell you what to do. My new Honda’s manual says to avoid ‘sudden’ and ‘full throttle acceleration’ for the first 600 miles. Based on your description of the trip you are going to make, I wouldn’t do it until you’ve put at least 600 miles on your car.

Personally, I always double the recommended ‘break-in’ period on my new cars.


#9

Ok, what if stick to low speeds (fluctating between 45-65mph) for the 80mile trip nonstop? I dont have the manual yet as i havent bought it yet.


#10

I think your planned first trip is pretty much ideal for breaking in the new engine. Don’t use cruise control and vary your speed and I don’t think 5000 rpm is at all excessive. Go for it.


#11

And those saying follow the manual is the “balking” I was talking about. Check my link. It works. And works well - owner’s manuals be damned - you don’t need it. New cars don’t require the old methods anymore.

This is, probably, the single time I’ll disagree with the manual, however.


#12

Your engine was broken in by the time you got home from the dealer with it. Seriously.
Now just drive it normal.


#13

If you just drive it like you drive any car, that will likely cause no more problems than it would cause an already broken in car. If your objective is to keep this car for many hundreds of thousands of miles though, it might make sense to go gentle for the first few hundred miles. But that’s only if you really want to extend the life of the car for as long as possible. Most people sell their cars after 3-8 years, so it wouldn’t matter for that. Whatever problems you caused by an overly aggressive break-in period, you wouldn’t own the car when it came time to deal with those.


#14
The owner's manual will tell you what to do. My new Honda's manual says to avoid 'sudden' and 'full throttle acceleration' for the first 600 miles.
Yeah, but with a 78 HP motor, it's kinda hard to avoid full throttle and not get run over, no? Obviously, not being a road hazard takes priority over "perfect" break in! However, I would not hesitate to get in the "truck lane" and go slowly uphill, if it keeps you from a downshift. (Usually, you can tell when giving it more throttle will result in a downshift, or at least I can.) I know people who will FLOOR a car to maintain 75 on the upgrade, and to heck with downshifting into second! To me that just seems unnecessary.

One specific thing I’ve heard as a recommendation, is to lock out overdrive, then accelerate from HWY cruising speed to about +10 above, then coast back down to cruise, repeating this cycle a half-dozen times or so. This is, I’m told, to properly seat the rings–the manifold vacuum helps draw oil up over the rings, and the acceleration helps them conform to the cylinder walls. Don’t know how much difference it makes, but it at least gives you the illusion of “doing something” to help out…passes the time, if nothing else, and probably doesn’t do any harm.


#15

I’ve always believed that it makes sense to break a new car in the same way I intended to drive it, less any hot rodding, and it’s always worked beautifully for me.


#16

I’ve never had any problem either following the manual. Geez even my snow blower wanted it run for a couple hours no load. I guess all the engineers are nuts. I remember way back in 1970 we were discussing this at summer camp and one of our truck drivers said he took his new cars out and drove the heck out of 'em right off the bat. I guess it just shows how durable the engines really are now to be able to take the abuse that some folks put on them.


#17

Keep the Corolla and you won’t have this to worry about. ; )


#18

GeorgeSanJose wrote: “If you just drive it like you drive any car, that will likely cause no more problems than it would cause an already broken in car.”

I agree, but I think the manufacturers’ suggestions are made based on the assumption that a lot of people don’t drive “any car” the way it should be driven.

They used to say to limit your speed to under 55 mph or so for the first couple thousand miles have passed. I think now that they just want people not to do anything real stupid while the car is new so they won’t have to repair it under warranty… :slight_smile:


#19

Can’t remember where I read it, but one automotive journal suggested changing the oil/filter at around 800 miles, then 1500 miles. This seems to makes sense.


#20

If the car has 4 or 5 miles on it by the time it’s purchased then it’s already broken in. The cautionary statements in owners manuals are part of the CYA treatment in an effort to keep someone from doing something really, really stupid and then return to squawk about why their new engine bit the dust already.

Many high end cars, and even some motorcycles, have cautionary statements in their owners manuals also but they’ve already been run up on a factory dynomometer before even being shipped to the dealers. The average ho-hum Camry or Taurus won’t get this level of testing but Porsches, Audis, Harleys, and so on will.

The same goes for some crate engines which are also run at full bore on a test stand dyno before being shipped to the customer.

When I was in the aircraft shop we mounted every rebuilt engine on a test stand and rolled it outside for testing; and which included wide open throttle. This was on 4 cylinder Lycomings, Continentals, and even the older Wright and P & W 7 and 9 cylinder radials which had to be propped by hand.