So, the amount of damage from a hydro locked engine, depends on the engines speed when the liquid was ingested.
Also, the amount, type of liquid and how it got in, will have a major effect on what happens. So, when your engine first encounters a bit of extra liquid in the cylinders; your engine will begin to misfire. However, if it’s just a small amount of liquid, it might just, blow it right out the exhaust. But, if more liquid is drawn in, you’ll hear a loud knocking noise as the cylinders fill up.
So, it could be just a second or two and then your engine will shut off with a thud.
By and large, the most common is, water entering the air intake. Water can enter the intake on any engine, whether it’s from driving through water or an actual flood.

Also, engine coolant, can enter the cylinders, when a head gasket blows. A failure in the carburetor or injectors can introduce, liquid gasoline or diesel into the cylinders.
The real damage occurs when a large volume of liquid, makes its way into the cylinders.
Also, with higher engine speed, comes more engine damage. ( Almost sounds like a quote from Spiderman )

The reaction forces involved will almost certainly, break internal components like:
Again, the amount of liquid ingested and where it came from, will reflect the amount of damage.

The hydro locked engine was a symptom, not the cause. So, if the liquid was introduced to the cylinder, through a failed component; typically the head gasket, this must be repaired.

So, coolant is corrosive to the internal parts of an engine. As a result, when you leave this standing for any length of time, the damage will only get worse. Also, remember engine coolant, eats bearing material.
Consequently, a hydro locked engine, can also occur, when the engine is not running. Flood damage, for example. Fluid fills the cylinders, while the engine is not running and the starter, can’t crank the engine over.

So, the best thing to do is, avoid drive through any flooded streets. But, if you do, slow down.
So, the most disconcerting aspect of a hydro locked engine is, that it can strike without warning. That’s why regular maintenance and inspections, are the best way to keep on top of this issue. Preventative maintenance, is a lot cheaper and much safer, than a hydro locked engine.