Last week i put a new 180 t-stat and coolent temp sensor in and friday evening left camping and got about 30 miles and noticed the gauge needle was a little past the last 0 of 200 degs ! I was pulling the camper which weighs about 4500 lbs but should it run that hot and about what temp is that ?

 

Putting in a lower temp thermostat doesn't increase the cooling ability of your truck. All it does is allow coolant to circulate at a lower temperature that your engine wasn't designed for.

Is 180 stock? I was under the impression that 195 was the typical. With that being said, 200 isn't abnormal I don't think.

 

Did it stabilize after it passed the second 0, or did it keep rising?

 

Coming back on monday it did rise some more towards 260 but i stopped and checked and it didn't seem to be hot or even run bad ? I got the 180 because thats what i thought it had in it but when i got it apart i found out but figured i would change it later !

 

Is the cooling system full? How old is the radiator cap?

 

In my experience it's pretty hard to get these things to overheat. Did you top the coolant off after changing the stat? Your radiator could be partially clogged or something.

 

Did you have the engine running when you were adding coolant? I doubt that you have air trapped but I would check all possibilities. How hot was the outside air temp when you were driving? Was the AC running? Once temps hit 110°F+, I usually can't run the AC or it will slowly start to overheat. As Hey you said, how old is the radiator cap?

 

new cap ! It was about 85 outside and it doesn't have air in the system !

 

Start with thoroughly flushing the system then.

 

I would not blame the thermostat, i have 180 in mine from hughes with no issues, runs cooler even. +1 for flushing system.