Leaving the engine running not only bugs the person next to you , but also helps the enemy locate you . Once they locate you , they locate the friendlies next to you. This is the same for the new tanks as well. I understand the reason for having the engine on so you can get into a fight area, so here is what I do. I will find an area along the perimeter of the fighting and stay off to the side of friendlies.that way I can run my engine a little bit more.