i own a 1999 ford f-150 with a v6 auto trans
i have only had it for about one month
i was driving when i noticed a dash light on and my water temp gauge
was pegged out i pulled over opened the hood the engine didn't seem to be any hotter than usual i opened the cap on the reserviour
it had no water in it
i put about half a gallon in it and it was to the cold fill line
none of the water sucked into the radiator
i started the truck up the dash light was off and the gauge
was right where it normally is
this is probably the newest car i have ever own
haha i know thats kinda hard to believe i just like the older trucks

my question is
did the light come on and the gauge pegg out becuase i was a little low on water or was my truck really over heating?

 

Yes, I think you really overheated it.

The light and gauge are not coolant level sensors. They really are there to let you know the motor got too hot.