The dash is lying to you believe it or not.

 

There is also another issue that is CHEAP and easy to fix. The radiator cap that came w/ the pickup spring gives out causing a loss of preasure in the system. Going to autozone you can pay 6 bucks for a new one and it will allow you system to preasurize back up to 16PSI witch makes the boiling point of 50/50 coolant mix over 268F where the stock one after it gives out only allows preasure generally between 4 and 0 PSI meaning the boiling point will be below 240 closer to 230 F meaning your trucks system will boil critically reducing cooling and destroy stuff. Also you fan does not kick on tell about 230-240 PSI meaning by the time your ruck cools it will be very hot.

Your thermostat may not detect high temps because 1 its cheap and 2 the heating is coming from the core of the engine and may take a min or two to get to the theromostat.

Hopefully this answers helps I wrote it quick at work so I also hope it makes a little bit of sense.

 

ummmmmmmm 2 year old thread