Temp gauge on the high side

I have a 92 f-350 that I have had for about three years and the temp gauge had always read no hotter than O (nOrmal). I was driving home today and all of the sudden it went to the A and held there. Could this mean the thermostat needs to be replaced or maybe the water pump? Any insight woould be great.

it could be the thermostat or the water pump.

first thing to do, which should be routing maintenance anyway, is to flush the radiator. you can get stuff you put in that flushes and cleans it, then drain it and replace the water/coolant mixture.

it could just be a blocked radiator, restrictive flow leads to poor cooling and a raise in temperature.

if the flush does sort it then take it to be looked at, i'd do the flush anyway as it's not in the least harmful and is good maintenance.

just put a thermostat in it

Being a 92, it could probably stand a good flushing, and a thermostat, as has already been suggested. Visual inspection of the inside of the radiator will tell you if its clogged or not. The thermostat is a good, cheap place to start troubleshooting. But temp sending units go bad too. I use a candy thermometer to check the actual temp of the coolant at operating temperature. If you borrow your wifes, or your mama`s, just dont get caught. The temp should be within a few degrees of the rating of the thermostat. Around here, we have alot of minerals in the water, and it`ll clog a cooling system pretty quick. Always use anti freeze, or distilled water if possible, if you need to add coolant. The little you spend for the distilled water, will pay for itself.

Thanks for the respones, I had to take the radiator out and have it check about two months ago because it was leaking from the side, they reclamped it, preasure checked, flushed it out and all was good. so it has newer fluid in it, I may try to swap out the thermo, does anybody know where the sending unit for the temp gauge is located? I tried to look it up in the book but found nothing. would it be worth my while to add a different gauge?

What engine do you have, that will determine where the sending unit is? Adding an aftermarket gauge is a matter of choice. I prefer thermocouple operated units to electric, and i like to see the numbers, instead of a hand moving between hot and cold. But the factory gauges are accurate enuff, you can usually find a spot big enuff to mount one in dash, instead of hanging it underneath.

5.8l v8 351, I am thinking of adding an oil and temp gauge. Are they easy to install?

The coolant temp sending unit on the 351 is behind, and just to the right of the distributor, it has one wire. The coolant temp "sensor", is on the front of the motor, and has 2 wires , and sends info to the computer. Installing a temp gauge, or an oil pressure gauge is fairly easy. Just make sure you route the wires, and tubing away friom the exhaust, and if you have to drill a hole in the firewall to pass them thru, put a grommet in it to keep them from chaffing or cutting.

thanks for all the info