hi guys, i think i read that this is a common problem before but why would when my truck warms up completly the temp guage will read like 190 then all of a sudden it will drop fast down to like 150 for a few seconds then go back up. it will do this back and forth. the guy put a new radiator in it before i bought it so idk.

 

Sounds like a faulty t-stat

 

they all do that mine does it my buddies truck does it its normal i think it because the cooling system is so big that the coolant in the radiator cools reall fast and then when the t-stat pops the coolant change is pretty big

 

thats what i thought..
im not worrying about it then.
thanks

 

They will all do that unless you have gone to the new upgraded thermostat from Cummins.Do not buy one from anywhere else(Cummins-Mopar) as your only asking for problems.

 

yup i just went for a drive and checked mine and it does the same thing. From about 190 down to about 160 or so. then back up to 190. that temp change over and over cant be that good for the block and heads

 

190 to 160 isnt anything to worry about.Its just the thermostat allowing flow quickly.Mine almost seems like it "pops" open

 

i havent been in a dodge with the cummins that doesnt do that

 

yeah im not worried about it then. thanks tho

 

Mine done it, stuck a new t-stat in, and it quit. I'd probably do it considering it may still be the stock one.