Engine/Transmission (1994 - 1998) Erratic water temp gauge.

[c-hawk]

I'm hoping i can get some suggestions or thoughts on what is going on with my truck.



It's the 96 from the sig. below.



Ok, so the gauge works fine, completely normal, and seems to be accurate until the truck is warmed up.



Once the truck is warmed up, the gauge will swing down to about 150* in approx. 3 seconds. (from 190*) Then it will steadily work it's way back up to 190*, taking about 10 seconds to get there. Once at 190*, it will swing back down to 150*, taking about 3 seconds. This just repeats basically the whole time i'm driving.



This happens running on flat ground, unloaded. I've never noticed a temp over 195*. Any thoughts would be appreciated.



Chris

 

[MPalachuk]

Try changing your thermostat, I think they have a updated one for it but I dont know the number.

 

[CTait]

I am glad you asked the question as mine is doing the same thing. I have owned the truck two months and only driven it three times so I didn't know if this is normal or not. This is also my first diesel.

























1995 2500 4x4 Ext. Cab AT.

 

[BigPapa]

This is normal. I've been told that Cummins has a thermostat that will not do this as bad. I'm used to mine. Just doesn't bother me anymore.

 

[GAmes]

I just replaced my thermostat with the new revised "won't do it now" one. It still does it if I am unloaded. While pulling any size trailer it settles down at about 140. Once the temps get up into the 80s and 90s maybe the swing will stop.

 

[LRamey]

I had the same problem when I first changed mine. I went with an aftermarket one from NAPA. I spoke to a friend of mine who is a CAT mechanic & he said it isn't normal, & I've never seen it do this with any other vehicle I've ever owned so I agree'd. I bought one from Cummins & the problem went away.

 

[tURBOdIEZEl]

my truck does the same thing... . i actually noticed it on a road trip from tx to pa... . its taken that same road trip 5 times..... ive accepted it as a norm even though it is quite bothersom

 

[c-hawk]

Thanks everyone.



Looks like i may try changing the thermostat. Seems some have had luck doing this, and some haven't. I guess it's worth a try.



Thanks again, and if i figure it out, i'll let you all know.



chris

 

[Rams-n-Hogs]

Mine has been doing that since the truck was new. I've always considered it normal. If it ever starts acting different, then I'll figure something is wrong. I'm still on the original thermostat.



Jim

 

[fishjack1]

FYI - this excerpt off the dodgeram.org site:



"Wide fluctuations of the temperature gauge the result of a large radiator, it is relatively harmless and normal Cummins has released a revised T-stat that does fix the "problem". The revised T-stat Cummins part number is 3934373. (The old T-stat Cummins Part number is 3928499. )"

 

[c-hawk]

Ok, so maybe i'll just leave it as is. Long as it's not hurting anything, i'll save my money.



Thanks again to everyone.



Chris

 

[Deezul1]

All it is, is the stat opening and closing when its supposed to and the gauge registering the temp changes as its supoosed to. The cooling system is so large that an unloaded truck cant keep the coolant warm enough for the stat to stay open so thats why the cycling happens.

 

[gds3076]

My truck has been doing it since I have owned it. I have noticed that when the truck is loaded the temp doesn't change all that much. but when the truck is cold the temp gauges swings all over the place.