Anyone knows what the normal operating temperature on a v-10 should be?

I'm not sure if my coolant temp gauge is messed up or my thermostat is stuck on open, but I can't seem to get the truck to really "heat up". When I drive it around town the temp gauge will show around 150-160, but even when I was towing a 8,000lbs trailer through the mountains up on 7% hills in 80+ degree weather I never managed to get to 200F. The middle line of the gauge is 210 and I never even came close up them hills...

Am I right to worry?

 

Well, below 180 and cylinder wear starts to go up.. At those temps it may very well be running in open loop as well.. I would change the thermostat and go from there.

 

On my truck the gauge isn't accurate at all. Before I replaced the radiator it overheated and boiled over, spewed coolant everywhere but the gauge was still a little below 210*. I would try to get a temp gun and measure the temp of the upper radiator hose, it may be running the right temperature.

 

after allowing the engine to warm up to around 180 deg, i've noticed it generally stays between 180 and 190 deg the most of the time and i have never seen it climb above 200...the only thing i can think of is that the cooling system (radiator, fan, coolant capacity) is beefier than its V8 counterpart, allowing it to keep the engine from overheating...remember, these trucks were built to be workhorses

 

Did the engine overheating warning light come on when that happened?

That's what I was thinking. But when I go up, lets say, 5% hill for 2 miles and my gauge shows the temp at around 190, and then let it go down the hill, within a mile down the hill my gauge is down to 150! Since the OEM thermostat is set at 190, there is no way the engine will cool down to 150 just on ambient temp...

Well, I just ordered the thermostat, PCM sending unit and the gauge sending unit from rockauto. The gauge sending unit cost me $8 after the dealership quoted me $77 and change last night for the part! And $30 some for the gasket I just ordered for $0.99! Never seize to amaze me...