I have a 92' Ford Ranger with 2.9 V6 and auto transmission.
I had a remanufactured Jasper engine with complete engine kit installed about three weeks ago. The engine is running warmer than the old engine (when old engine was in good condition).

These are all the parts that were replaced along with the engine:

radiator/radiator cap/water pump
all hoses
all belts
PCV
thermostat (180 degree)
fan clutch
plugs, wires, cap rotor
all filters

Coolant temp gauge is still in the normal range, but I don't like the fact that a very expensive engine is running warmer than the old engine. When I turn on the A/C, the needle goes to the top of the normal range. So I am not using A/C right now. The mechanic said A/C compressor front seal is going bad. But even with A/C off the needle goes a little over halfway.

What else should I check? What about water temp sender and coolant temp sensor? These were re-used from old engine.

 

I assume that you have verified that the coolant is topped off and of at least a 50/50 mix of new coolant. If so, have you checked the actual coolant temp? I would use a heat scanner on the thermostat housing. You may just have a faulty engine temperator sending unit. The coolant temp sensor is for the computer, so this should be no issue. Sometimes you can ger an air pocket under the sending unit if it's a top mounted unit causing the gauge to read high. This can eliminated by loosening the sender and bleed out the air until coolant bleeds out.

 

Yes, the coolant is topped off to the top of the radiator filler neck. I assume it is a 50/50 mixture. It has a rich green color.