[sorin1987]

I've had my 2020 G31 for about 4 months now. Previously I had the 3.0L E90, which didn't have the SS function. I find this function useless and even annoying especially since I do a lot of city traffic driving and sometime the engine would stop just to start after one second because I just stoped at a Give Way sign or I stopped behind a car and that car decides to move for 2m forward (I think the car has a sensor that detects if the car in front moves and it starts the engine again thinking you will move but you are still in a line and I wouldn't move). So I disable it, when I start the engine I press both the Start and the Disable SS buttons at the same time.

My questions are:
Can this function actually harm the engine and components if I it starts and stops so many times, even within seconds? I know my driving instructor (from 18 years ago) kept saying that starting and stopping the engine is harmful and if you can you should avoid short car journeys. Also would it damage the battery life by keeping the engine off but the AC and infotainment on?

Would it save any petrol? I assume that is the primary reason for this to exist. But I am not sure if when it starts the engine it will pull more petrol (like the old cars used to do) and therefore negate the saving it did while stopped.

Thanks