Please help I have a 2001 dodge ram 4x4 5.9 the check engine light came on an threw a code saying engine staying cold to long so I went to swap thermostat an before I put the new one in I checked the old one ..I boiled water an dipped it in an put in cold water an it is doing exactly what it's suppose to do ... so if it's not my thermostat what could be my problem an thanks for the help

 

It might be sticking part way open sometimes. Clear the code and see how the new one works. Could be a bad sensor? Check battery connections and any ground wires you can find.

 

Thanks !!

 

At what temp does the thermostat start to open? That code is fairly common for folks that have gone to a 180 thermostat.

 

Yea the thermostat that was in it was a 180 sso I changed it to a 195

 

I believe the 195 is what they come out with, while changing water pump with small leak, I put in new thermostat (the old was working alright, just was working in the general area). Now I notice it is running a little cooler, so there must have been a something hotter in there. So folks say they run better when hotter, I don't know, just went with standard.