i keep seeing pictures and videos of this and i'm wondering how do people get it to happen. is it with mods or something in-game i'm missing?
They may be turning HDR on and off to get the smoke to come back... However, it's getting repetitive to do that every time they start up the game.
In the current version of the game that happens whenever your car overheats/drives through water, thanks to added thermal simulation. Are you using a current version of the game?
You can tell the game, that whenever a vehicle is spawned, its engine won't be preheated. That makes the engine emit white smoke as well...