1994 ford ranger temp gauge

[DoubleFlash]

So this car has a lot of back story. When I got it,
The heater didn't work. I replaced the water pump, then it was working fine but only after getting to higher rpms. Anyways, before I replaced the water pump I replaced the thermostat, because my hot/cold gauge didn't work,
So I was hoping that would fix it, but it didn't. My uncle helped my maneuver a different style thermostat through my dash and beside the engine, so I could still see if my engine ever gets too hot. Lately it's been heating up to 240+, but only when driving in town or at a stop light. Once I get going 30+ mph it goes back to the normal, around 190-210. Could this be the fan clutch? An air pocket maybe? How could I trouble shoot this and take care of the problem?
1994 ford ranger 2.3 L

 

[Pacfanweb]

If it heats up at stops and slow speeds, that's typically a fan issue.

 

[heymrdj]

When it gets to 240 is does revving it help?

I would say if revving helps you've got an air pocket or a dirty water route. If it doesn't help, then I'd say a dirty route. Think of a clogged radiator or heater core. Either way, a flush is a first place to start, and be prepared to be changing lines, radiator, or core afterwards (sometimes getting rid of the crud ends up with leaking pinholes).

 

[Zenmervolt]

If it heats up at stops and slow speeds, that's typically a fan issue.

This.

Check for proper fan operation first before you go hunting down air pockets or clogs.

ZV