I have a 2.3l Mazda b2300 that I can’t figure out why won’t get to operating temperature. I’ve replaced thermostat with an OEM motorcraft thermostat,  replaced radiator and old coolant and flushed with radiator cleaner and distilled water, and also replaced coolant temperature sensory but still temperature gauge reads at just barely over “C” on cluster. I can feel heat coming out of my heater core when I turn it on so I don’t believe that’s the issue either. I’m guessing it may be my fan clutch constantly engaging fan, not allowing engine to get to operating temp. When I took the fan off the clutch and ran the engine for about 5 minutes I could see the temp finally rising toward operating temp, but then again I’m not positive if that’s a tell-tell sign the fan clutch is what’s keeping the engine cold. Any advice is appreciated.