Can i run my truck with no thermostat?

 

yes.

but your engine temp will only reach about 130*, you'll have little to no heat and your mpg will be a little lower than normal.

 

+1 on what Vaughan said.

 

Not sure heat is going to be much of an issue in hawaii.

 

You can absolutely run your truck without a thermostat; however, the resulting performance will be poor, at best since the engine will not be able to get up to the proper operating temperature.

 

LOL, you never know. he might be on top of one of those snow covered dead volcanoes.

 

What is the optimaal operating temp for the 5.9l engine? 190?

 

stock tstat is 195. you can run a 180 to be a tad cooler but some people get a check engine light with a 180.

 

humm.. wonder what is wrong with mine then.. just recently it looks like it is more like 180is.. heat is warm.. not hot.. when i put that one in last year it was hot.. only 34 out today but just not warming up all the way..

 

tstat might be getting a little weak. if its old, replace it with a Stant Superstat in the temp of your choice.