[OUGrad05]

For years I kept the auto stop/start system off on my car. I found it annoying and was concerned about long-term negative consequences of using the system. Excessive wear on starters, oil pumps and water pumps and other mechanical components were my top concerns.

For the last 6 months I've been using the system, mostly to see if I could a) get used to it and b) what sort of MPG differences it would make over the long run.

I am saving more gas than I gave the system credit for in the past. I'm saving about 1 to 1.2 mpg, which considering I don't have a lot of stop and go, is not bad. If I lived in a big city with real traffic I suspect one could double that number pretty easily.

However, some of my concerns about long-term wear and associated costs remain. My vehicle is a 2015 335i and I have some friends with 2012 and 2013 cars and a couple others with 2016 and newer cars. It's a mixed bag on those who use it regularly and those who turn it off. I have a lot of quick stops which have the engine shutting off for a mere second or two, sometimes less, I can't help but think that's not good for the vehicle.

Any thoughts, comments and/or experiences?

[GoneIn4Secs]

This has been discussed

But the benefit is too low of gas saving, and more unnecessary engine wear of constantly start stopping

Plus try driving in bumper to bumper traffic on the hwy with this function on, and see how stupid it is

[Mason Hatcher]

I have no idea about premature wear and tear, but I am not using the feature. I turned it off on the test drive and it has been that way since.

[obert]

Lots of people say that it leads to early N20 timing chain and guides to break. Just google or search N20 timing chain issues.

[tracer bullet]

I have mine off. I like it as an option, but for me it's as mentioned - typically seems to be off for just a couple of seconds. Lights around my area are pretty short compared to some parts of town where you can actually sit a full 2 minutes or more before they turn.

[Alfisti]

Absolutely DESPISE it, complete insanity to have this as th default setting, ridiculous. Guarantee you it slowly kills the car.

idiots.

[The0pportunist]

In my last 2 cars, turning off this feature was a part of the start up sequence.

[Grip Addict]

Originally Posted by Alfisti

Absolutely DESPISE it, complete insanity to have this as th default setting, ridiculous. Guarantee you it slowly kills the car.

idiots.

It is not the default setting.

In ///M cars it is defaulted to off.

[GoneIn4Secs]

Originally Posted by Grip Addict

It is not the default setting.

In ///M cars it is defaulted to off.

Its on by default on comfort setting, but it will remember your setting

[Alfisti]

My wife's 35i X3 it's default on. Loathe it.

[ddk632]

I was laughing earlier today sitting in traffic with my engine idling, auto start/stop disabled as it is 100% of the time.

The lady next to me kept inching forward a little at a time and each time her engine cut off and restarted.

How does anyone even get used to that, it's beyond me.

[Grumpy Old Man]

I had it on a loaner a few months ago, it drove me crazy until I figured out how to turn it off....

[Zanity]

I use it on 1 intersection only because I have to wait almost 5 mins for turn left, that or wait for a train, other wise, i never use it. I remember reading that our starter is guaranteed 50,000 start/stops, then its unknown territory after that for reliability. Not surprised its only made to last till warranty.

[Fliplegend]

I used it once and that was the last time. The delay in acceleration from a stop immediately frustrated me and off it's been thanks to bimmercode.

[AlpineX]

Between the compromised charging system and all that extra chain loading, no thanks

[jcbaxter1975]

Coded it off. I agree with others that it will lead to premature wear and tear. If you have to put in a new starter early, that mitigates any savings on fuel and reduced emissions.

[OUGrad05]

Originally Posted by jcbaxter1975

Coded it off. I agree with others that it will lead to premature wear and tear. If you have to put in a new starter early, that mitigates any savings on fuel and reduced emissions.

Agreed, appreciate the feedback, seems like most are generally in agreement.

[cfm56d7b]

Used it once and found it far too invasive. Never used it since.

[tuco44]

Turned it off on pick up for my last two cars. Never use it, and won't be using it, ever.

[MacklinUSOB]

Incredibly annoying on an MT, incredibly annoying on AT, purported increase in TC wear leading to failure.

Sucks all around. Code it off and live a happier life.

[Derek Mc]

I have a now 45 month old Mazda 6, I let the S/S do it's thing from day one and absolutely nothing has broken nothing has failed, nothing squeals creaks or bang but it has saved me in 61K miles according tom the computer 3200 (and change Miles worth of fuel over the piece. I live in Scotland where commuting my 41 miles each way takes over an hour and around ten to fifteen minues otf stationary traffic.

I am sure BMW will be no worse than Mazda for equipment robustness,,,,

[Billfitz]

Originally Posted by ddk632

The lady next to me kept inching forward a little at a time and each time her engine cut off and restarted.

BMW's don't do that. They travel a set minimum distance, perhaps 100 feet, before the engine will shut off. BMW engineers may be dumb but they ain't stupid.
ASS is kind of like the weather, as everyone talks about it but no one does anything about it. That would be to have two otherwise identical cars drive 100k miles on the same route, one using ASS, the other not, with the two engines torn down and examined to see the difference. Anything else is pure speculation.