ok, my truck does the whole thing on how the needle jumps between 190-140. i heard that can be fixed by the new thermostats from cummins. is it realy nessasary to change it? will it hurt anything the way it is now? whats the p/n for the new one?

 

my 94 has done that since I first bought it, I dout it will hurt anything

 

thats what i was thinking. it always just catches my eye and worries me

 

dan dont worry about it its not like a gas engine were they constanl stay open they open around 180 which is when you see it drop i was worried about it also when i rebuilt my motor went threw 3 thermostats from cummins and they all did it

 

Dunno why, but some trucks do it and others don't. Mine doesn't normally, but we had around 15 Dodges where I worked a few years ago and they all did it. 96 and 98 12v mainly but a couple 24v as well.

 

Mine used to float around then my rad sprung a leak. So I chaged it out along with all the hoses and put a new Cummins T-stat in. I also used Global Charge coolant and flushed the system. Now my gauge climbs up to 180* and rides it....it moves a little in the summer when towing but usually stays right around 180* all the time. That actually bothered me for a long time cause I was used to the temp gauge swinging.

 

i was just wondering the same thing, my truck will be all warmed up at 180 , next thing i know it is below 140 wierd aint it

 

Perfectly normal, even the new cummins t-stats do it, will not hirt anything.

 

I recently installed the updated thermostat from Cummins, and I am still getting a 10* temp swing.. I really see no harm as long as it doesn't go over 200*