That's something I have been wondering about. Salt water
is seriously bad for mechanical and electrical systems. In the case of a car, the cost to repair those systems might outweigh the value of the vehicle. But it doesn't melt or dissolve. Given time and money, you could strip it down and rebuild it.
However, in NYC after Hurricane Sandy, the City was claiming that anything and everything touched by salt water was completely irrepairable and needed to be replaced with brand-new (at the Federal taxpayers' expense, of course.)

Take something like a large electric motor, for example. Say it costs $10,000 to replace. Might it be worth a couple grand to have a tech tear it down, wash it with distilled water, dry it in an oven, and rebuild it like new? They even managed with straight faces to claim that
pavements that had been inundated by salt water required complete replacement due to the "chlorides" in the salt water.

Seriously, NYC has winter weather, and spreads rock salt on the roads to combat icing. The salty slush and water gets splashed everywhere.
Mynock wrote:Calling a Toyota Celica a sports car........BWA HAHAHAHAHAHAHA.......ha.
But yea, even if they get it out it's totaled. Submerging a car in salt water is only slightly less destructive than submerging it in molten lava.