scjfly

http://www.youtube.com/watch?v=pb9IX5QPmog

Hey guys, here is a video of my coolant temp gauge fluctuating. It does it under all conditions, city driving, freeway, etc.

I asked a diesel mechanic at a International Mx Facility who happens to have the same truck, and he said that it shouldn't fluctuate.

I asked a mechanic at the dodge dealership and he said the fluctuation is normal.

I read on Geno's that there is a replacement thermostat that should help with this?

Question is, is this normal or should I change out my thermostat? And if so, should I go with the standard Cummins thermostat or the new one?

Thanks for helping.

Clark

cj360trider

mine fluctuates as well a t stat from cummins will prolly take care of it if it bothers you. as long as you arent getn hot and you dont mind watching the temp gauge move around alot itll be fine. the cummins t stat is built much better than most aftermarkets

patdaly

Bet it is an aftermarket T-stat. I don't have a Cummins place close, I replaced mine with the premium Napa brand and it works much better, still fluctuates, but not nearly as fast or as far as yours does.

Robert Rausch

Mine has been fluctuating for 287,000 miles. I think it's normal.

infidel

Totally normal, read your owner's manual.
Mine have been doing it for over half a million miles.
I would start worrying if they didn't do it.
You really only have two choices, load the truck up like it was designed to be used or get used to it.
Attempts to fix it with a different thermostat usually result in the engine running even cooler.

In 1998 after getting tired of people complaining Cummins electronically changed the coolant temp gauge into basically an idiot light.
Personally I'd rather have a gauge that tells the truth.

Robert Rausch

I like it that way. When I'm pulling a load I can tell just how hot the water in the radiator is by how low the temp gauge goes when the t-stat opens and the engine takes a drink of coolant. If the radiator water is really warmed up, the temp gauge only dips a little bit--if the radiator water is relatively cool, the temp gauge dips a lot.

scjfly

Thanks guys for all the info! I guess i'll sit tight and not worry about it, but I'll replace it with the cummins part when I do a coolant flush.

This forum is great!