Fluctuating water temp. gauge....

[Archive]

My water temp needle all of the sudden seems to have a mind of its own... Its at 140, within 5 seconds is at 190, then bonces back to 140.

I test drove another Dodge Diesel that did the same thing. . ( That was half the reason I didnt buy it. Figured more was wrong. . )

I checked the coolant, all is well. The radiator is not hot, or at least to the touch.

Is this a common problem? Or should I just go ahead and buy some mech. gauges and forget it?

 

[Archive]

Search the archives and you will find alot of info on this. It's normal. There is an updated thermostat available from Cummins that will supposedly cure it. Personally, I like it. When it stops swinging is when I pay attention.

Bob

 

[Archive]

<font color=red>Mine does the same thing. It seems to me that it's just the thermostat opening and closing. I've got 139,000 miles on it and have had no overheating problems.
Just my $. 02

------------------
"Big Red" 1994 Ram 2500 Laramie SLT, 12 valve, 2WD, Auto. 139,000 miles. I am my own warranty station Ranch Hand steel brush guard, Scotty Air, silencer ring removed, Flowmaster muffler, chrome turn down pipe out the side, Velvet ride shackles. www.gitchesumatfreeweb.com

 

[Archive]

Its normal. I put the non-cycling T-stat in last year. Still did it.

On an interesting note. To make a long story short. I had an Autometer Mechanical Water temp gauge. I mounted the "probe" where the Fitting w/ the check valve screws in the head. Attached to the rubber hose on the themostat elbow. It is designed to purge air from the cooling system on refill.

The T-stat would open at about 190 degrees (NEVER saw it open that high) and settled down to 180 and did not cycle anymore.

I pulled the gauge because of a sticky needle. Both ports on the t-stat elbow and the 1/2 check valve fitting are temperarily pluged with brass fitting. The temp cycles like before.

I will reinstall gauge and take thermocouple measurements (length & width) . I will drain some coolant and look into the check valve port to see if I can figure out why the temp probe screwed into this port stops all cycling.

 

[Archive]

Had the cooling system on my truck flushed. Put new uppper and lower hoses on. Ordered the revised T stat and installed it. The revised stat goes up and down for the first few miles then will stay steady once warmed up.

 

[Archive]

Had the cooling system on my truck flushed. Put new uppper and lower hoses on. Ordered the revised T stat and installed it. The revised stat goes up and down for the first few miles then will stay steady once warmed up.

 

[Archive]

This is normal. Mine will do it with stop and go driving. Usually steadies for highway driving. My temp reading never has gone over the half way point.

 

[Archive]

Bug Out:

My truck started doing the same thing at
the end of last year. I had the Dodge
dealership install the new Cummins
thermostat and the gauge quit
fluctuating.

------------------
Red '96 4x4 2500 Auto 3. 54, TST #5, Pump Mods, Banks Exhaust, Prime Loc, Cummins Chrome Kit, Pro-Torque Converter, BD Valve Body, Sendel 16" Alum Wheels w/ 33" BFGs

 

[Archive]

Bug Out,

This is normal. It will vary according to the outside temp. On cold days it will do it more since the engine takes longer to get up to the temp to open the stat while the coolant is getting colder in the radiator. When it opens the temp drops. On a hot day it doesn't fluctuate as much. This is one of those if it's not broke don't fix it. No sense spending money to fix a normal operation. My truck has over 143K miles and absolutly no problem with the cooling system. It still has the factory stat in it and still fluctuates.

------------------
Joe George
Eureka, CA

'95 2500 CC auto 4X4,3. 54,Combo EGT/boost guage,custom switch panel,PacBrake,TST #5,BD valve body,Automatic motorhome steps on both sides,Foldacover hard bed cover,Cummins chrome kit,Black steel grill guard,Front hitch receiver