mssca

I completely forgot about the break-in period of a new vehicle. I know almost all conventional vehicles have it. Lexus even officially published these guidelines on their manual and on their website:
http://lexus2.custhelp.com/app/answe...reak-in-period

But I completely forgot about it and the salesperson didn't mentioned it during the vehicle delivery either (2017 RX 350). When I got it, it had just 8 km on it. I have about 900km right now and I am not sure if I have rev hard during that period. What could possible happen now? Am I in danger of having mechanical issues in the engine in the future? I did drive 100 km distance at constant speeds about four days after owing the vehicle (at at that it was about 70 km on the odo).

I am bit worried now... any expert mechanics or technicians here? What is your opinion?
THANK YOU.

mspearl95

I asked the salesperson about break- in period, and they said it really doesn't matter, as the engines are already broken in at the factory before they are installed. Even the link in your post says that it is optional and the benefits of following their recommendations is marginal.

ravenuer

I wouldn't drive it out of the dealership and tow a heavy trailer or something, but just normal driving is fine. Engines are built much differently now and don't really require a special break in period.

ggebhardt

Like the other said, engine break in is not really needed anymore. Yours will be fine.

mssca

Thank you everyone for your replies. I won't worry about this
On another note, I found RX windscreen is very weak compared to Toyota Rav4 we own. For some reason my ONE month old windscreen already have a crack from a small rock chip.

minusplus

Just don't drive your RX350 like it's the IS F. I would still try to follow what the manual recommends, especially if you want to keep your car for a long time.

mikemu30

how do you know the Toyota windshield wouldn't have cracked under the same circumstance?

mssca

Someone who owns a NX told me the Lexus windshields known to spread the damage even after a repair. If the chip is close to an edge, it could spread to the corner. I also read a lot of threads here on that subject. I have a lot of chips on my Toyota Rav4 and all of them are filled/fixed and none of them resulted in major cracks.

Even the dealership guy said the triple pane or whatever the new method they use on Lexus glass is hard to repair and if the chip is closer to an edge, it will most likely spread even after repair (I went to Lexus to fix the chip because it is free chip repair for new vehicles). According to him, the glass is great for keeping vibration and sounds out of the cabin, but not good for chips. So...don't get chips close to an edge. But all of this is second hand information. I don't know by experience. Hopefully, this chip won't spread.

PeeVee

Those who lease or buy for mid term, they won't be concerned.

Those who buy for long term, the break-in is good for long term engine efficiency and fuel consumption.

Elation

No offense to your sales person, but "sales person" is not an engineer. They usually don't know anything more than customers..often less.
It is highly recommended to follow the manufacturer's break-in period procedure.
The car won't blow up next year, but it will definitely benefit from break-in your car properly.

Unless it's a high performance vehicle like the Nissan GTR, they are never broken-in at the factory.
They may rev it up to the redline, but that's not breaking it in. It is done before the internal component parts reach the normal driving temperature. So pistons, bearing, cylinder do not thermally expand to cause a wear.
When you take it out on the road, it's a different story.

Oldfart

https://en.wikipedia.org/wiki/Break-...anical_run-in)

Modern versus older break-in regimens

For many kinds of equipment (with automotive engines being the prime example), the time it takes to complete break-in procedures has decreased significantly from a number of days to a few hours, for several reasons.The main reason is that the factories in which they are produced are now capable of better machining and assembly. For example, it is easier to hold tighter tolerances now, and the average surface finish of a new cylinder wall has improved. Manufacturers decades ago were capable of such accuracy and precision, but not with as low a unit cost or with as much ease. Therefore, the average engine made today resembles, in some technical respects, the top-end custom work of back then.[5] For some equipment, break-in is now done at the factory, obviating end-user break-in. This is advantageous for several reasons. It is a selling point with customers who don't want to have to worry about break-in and want full performance "right out of the box". And it also aligns with the fact that compliance rates are always uncertain in the hands of end users. As with medical compliance or regulatory compliance, an authority can give all the instructions it wants, but there is no guarantee that the end user will follow them.The other reason for shorter break-in regimens today is that a greater amount of science has been applied to the understanding of break-in, and this has led to the realization that some of the old, long, painstaking break-in regimens were based on specious reasoning[citation needed]. People developed elaborate theories on what was needed and why, and it was hard to sift the empirical evidence in trying to test or confirm the theories. Anecdotal evidence and confirmation bias definitely played at least some part. Today engineers can confidently advise users not to put too much stock in old theories of long, elaborate break-in regimens[citation needed]. Some users will not give credence to the engineers and will stick to their own ideas anyway; but their careful break-in beliefs are still harmless and serve roughly like a placebo in allowing them to assure themselves that they've maximized the equipment's working lifespan through their due diligence.

ggebhardt

I always liked the theory that break in should be “drive it like you stole it”!

Not me.

guan01

My car is for long-term, so break in do not hurt.