If you have comprehensive coverage it will be covered. 'Flood' is a named peril listed in all auto policy contracts and most likely will be covered without a deductible.
No. Insurance does not cover mechanical problems.
Only if it was caused by a collision or sabotage.
Possible internal engine damage.
Auto insurance covers damage caused during an accident. If the engine is damaged during an accident that's covered. If it's damaged for any other reason then that isn't covered.
No. But if you have proof positive that the mechanic caused the damage, HIS insurance will cover the repairs. Call your local office of the State Attorney General.
perhaps failing oil pump caused engine damage
engine implodes
Engine, not motor, and that depends on your insurance policy. If you don't have flood insurance specifically, flood damage is typically not covered.
Oh yes!
Blown head gaskets.
the engine is flooded with gas
Most insurance agencies, including Farmers, will total a car with this amount of damage. It depends on where the damage is and if the engine and other expensive parts of the car have been compromised or totaled.