Keagan said:
What destroys flood cars is in two groups.
The interior is easy to describe, it gets wrecked with mold and nasty smells that pop up on humid days.
The mechanical killer is wiring. Every wiring connection in the car has gaskets to keep out splashing rain. Go pay $2 to go into a pick-n-pull sometime and just go around disconnecting connectors and look at how they’re made.
The problem is water has weight. Every 2 feet of water depth increase pressure by 1 PSI, or about 20 kPA per metre if you’re batting on that team. So 2.5 inches of covery is still 0.1 PSI, and that’s enough to push dank flood water right past those gaskets and into the interior of the connector where the contacts are.
However, the gaskets do a bang-up job of preventing the water from leaving! Thus they entrap the water and sit there corroding, corroding, corroding.
Now electronics are a different deal, either they get absolutely wrecked due to what corrosion does to a circuit board, or they are immune because they are “potted” (dipped in epoxy) But if the connector on their edge is corroded out, it’s just as bad.
Keep in mind, wiring harnesses are no joke. They are expensive kit - either to buy new or painstakingly remove from a wreck without damage. So the harnesses themselves are a “component” that can fail.
Add to it, the failures won’t be “dead car”, but rather “mysterious niggling malfunctions that take hours of expensive technician time to chase down”, and then an endless stream of problems like this. Because the troubleshooting trees are written assuming normal failure probabilities, not the most likely culprit is a connector.
If I had a flood car, I would deconstruct it, and painstakingly inspect every component. That’s a huge amount of work even for me, a DIYer, so the economics of it are pretty dubious.
Notice I haven’t said a solitary thing about ICE engine or transmission. Those might get off scot-free, with repeated vigorous oil changes. Worst case they need a conventional teardown/reassembly to polish up metal parts, replace gaskets etc.
The big battery, you’d have to crack it open and inspect it. Either water got in or it didn’t. Its water protection is a bit better than connectors. Honestly, stripping the battery and trashing the car may be the best use of a flood car… yank out the modules for EV conversion or a fixed battery array for backup power or grid arbitrage. One major solar field in L.A. absolutely fills containers with packs out of wrecked Nissan Leafs for that purpose, I’m sure he’d love to receive 1000 Leaf flood cars.
one thing you got wrong: inside connectors are NOT watertight. water inside a car is a disaster as it will corrode every connector it touches.