The engine pushes water out of the top hose, into the radiator, returning thru the bottom hose. Meaning the bottom hose is the closest to suction in the system. Factory puts a thing that looks like a stretched out slinky inside the hose to prevent collapse. Cheap hoses do not have the spring, and people forget to transfer them across. Certain conditions the hose will collapse and stop water flow. Instant overheat.
Fan clutch is a standard parts store item. Look at your fan, it's the silver thing that the blades bolt to. It allows the fan to slip when the engine is cold because the fan eats like 10hp. When hot the clutch locks up for maximum airflow.
Inside the fan clutch is silicone fluid. Normal failure mode is to leak that fluid out, and it's sticky. The #1 sign of a failing clutch fan is sticky residue around it's seal. All other engine grime is oily.
Electric fans have some advantages, but when converting the main concern is finding an electric that can move as much air as a mechanical. When the engine is revved up and hot, like a truck working under load, an electric can't compete with the air movement of mechanical. When sitting at a stoplight, the mechanical can't compete with the air movement of an electric.
You can also troubleshoot your clutch fan by locking it in with baling wire between the water pump and fan bolts. Or avoid buying a new clutch for an old beater that's only gonna live a few months anyway.