I PASS GAS

About two months ago my water temp gauge started acting strange. The gauge will read fine as the water temp comes up to normal. A while after that, the gauge will slowly (over about a ten second period) go to about two needle's width of min temp (140). It will hang there for a few minutes then slid back over to normal (again, over about a ten second period). From there it will oscilate back and forth occasionally.

Any ideas? I'd hade to just start throwing parts at it. I had to replace the oil pressure gauge a while back and it was about a $65 part from Cummins (Dodge wanted almost $300).

Thanks in advance!

infidel

It's totally normal for the 12 valves to do what you describe, in fact many 12 valvers would think something was wrong if it didn't do it.

I thought by '98 the gauge was made into basically an idiot light though computer programing. The coolant temp still fluctuates, you just can't see in on the gauge.
Maybe your computer reverted to "normal".

Junk Man

It is totally normal for 24 valves to be rock solid in the middle of the gauge when not towing up a hill. An aftermarket thermostat causes those symptoms on my 2000. You might want to measure temps with a thermometer. You might want to pull & test the tstat. Aftermarket tstats are 1/2 price of Cummins. The only problem is that they don't work. You may also want to make sure your radiator is clean.

GoinAndABlowin

Both my '95 and '01 do the same thing you described. 530,000 miles later the trucks are still both fine, so I wouldn't worry about it. The '95 did it the day it was drove home from the dealer.

I PASS GAS

Had my truck done this all along I would maybe live with it. I've had it for 7 years and this just started and I like monitoring my water temp. I've read too many stories about burnt pistons etc. So what's the deal on this issue? Is it something with the gauge/temp sensor, or do I need to look into doing a coolant flush and change the stat? It's pretty much time for me to do some cooling system maintenance anyway, but I like planning ahead...

wyododge

If you have to do some maintenance anyway, you may want to pull your radiator and give it a good washing, then a system flush. At that point you have ruled out something that you were going to spend money on anyway. I suspect that with that minimal of a change your thermostat may be sticking a little. Just make sure to stick to an OEM thermostat.

While you have your radiator out you can do a KDP kill at the same time. They can be an issue on our trucks. Red3quarter did a great write up on his here. His cover was correct, but there were loose bolts that he had to tighten, which is just as bad.

JMHO, HTH