I just bought a 1983 Bronco 351W and after a little mudding my temp gauge is reading on the very high side of normal. I have given it 5 baths and made sure to clean off radiator with the power washer (on both sides) and the engine and there is not a bit of mud coming off of anything. I have not over flowed so I did the following. I replaced:

Temp gauge sender
Thermostat
Flushed, Cleaned and re filled system with about 3 gallons of new coolant
flushed and filled the over flow reservoir

Checked it today after sitting for a day and it had sucked a fair amount out of the reservoir and it took a 1/4 gallon to fill the rad up to the neck. I let it run up to temp and turned on the heater (which seems to heat it up more, on the gauge) Then burped it in case there was air locked in it and a little came out. Tried that a few more times and just green fluid no bubbles. But the damn gauge still says getting hot.

I bought a new water pump but before I get into that, what do you think about the gauge? Now the temp was fine before I went mudding and I drove it home 2 hours at 70mph and drove it around daily for 2 weeks without it ever going past 1/2 way. No leaks, clean fluid I do notice that the top radiator hose does get hot but not firm.

I was thinking the water pump because of the top hose not getting firm and the heater actually making it a little hotter. I am lost I just wanted to check with you guys before I just started replacing stuff because I am unsure what to do.

Thanks,
Steve

 

These gauges aren't very exact, but you might want to check the firmness of the hoses from and to the radiator, and maybe do a radiator flush, but personally I would look very hard at the fa clutch, as it probably is the cause, with the engine off, try to run the fan, it should offer some resistance, turning maybe a couple of times if you turn it with enough strength, otherwise it needs to be replaced, since you already have a new pump, replacing the fan-clutch is quite easy to do at the same time.