Basics:
A simple concept, if the car makes contact with water in any way, there would be a splash sound depending on the speed/velocity and it’s mobility when partially in the water.
Different Splash Variants:
The splash sound depends on, as said, velocity and mobility near the water. So in that case, I will provide an example.
If a car is falling or driving at a high velocity into the water, they well be a loud or semi-loud splash sound, if the car falls from a small distance, then maybe the splash will be more quiet.
But for say, when driving slowly into the water, there’d basically be no sound.
When driving in the water but not entirely in it, like, your car wheel is partially in the water but you can still move to the car’s full ability, the sound that will play will be less of a “splash” and more of what car would make when driving on shallow water, but I am just going to still call it a splash.
Water Dripping:
When the body of the car touches the water in the slightest, there will be dripping particles on the bottom of the car, so when you get out of the water or are done driving just in it, there will be droplet particles dripping from your car.
This part is toggle-able just in case it causes lag.
Underwater Sound:
What I mean by this is when your camera is underwater, a sound will play for the duration you camera is underwater that will sound like, well, a camera underwater, like in those documentaries or something.
Every other sound will be muffled if your camera is underwater.
Optional:
If a car impacts the water at a high speed like 150mph or more, or from a high drop from something like the mountain, the car will then get partially damaged. The speed or velocity the car hits the water will be more fatal depending on how fast said speed is. When saying “fatal” I just mean as much as water can do to a car hitting it at any given speed.
