Symon623

First Dodge CTD, my temp gauge runs right at 190 or the middle mark all the time cept when I'm towing up or down a steep hill, when I go up a steep hill it climbs a couple of thicknesses of the needle, I hear the fan clutch tighten up and start howling and the temp soon comes back down to normal, when I go down a hill, it of course drops a bit. Not worried but I had a non-dodge guy tell me that it shouldn't fluxuate that much. Prolly needs a coolant flush? Coolant looks good, didn't test it though.

With an Arizona summer comin up, I'd like to fix it now if it needs it.

Usually factory gauges aren't that active.

Anyone have a suggestion?

Thanks

macattack_ga

T-Stats in these trucks do that. Pretty normal.

DL1221

Yes its totally normal. Unlike gassers, the temperature gauge will move up and down on these engines all day long. Coolant starts to warm up, needle goes up, thermostat opens, coolant gets cooled by radiator, needle drops, thermostat closes, and the whole cycle repeats over and over.

However, one thing to point out on these 24-valvers. The puke bottle (blowby bottle) is mounted right behind the fan on the timing cover. What happens over time is that oil vapor will mist out of the bottle and completely cover the fan and the back of the radiator with oily dirty gunk. This can get so bad that it actually starts to restrict air flow and will make your engine run hot. The only good fix is to take out the radiator pressure wash it clean with degreaser, then relocate the puke bottle.

So do a good flush, clean the outside of radiator, and add new coolant (diesel coolant), and you should run cool all summer long. I did all this on my 01, and I also changed my thermostat to a 180*, the factory is 190* and now I run way cooler.

Symon623

Thanks for the input. The back of my rad and fan are quite clean? I bought it in january with a new LP and IP so I think either they washed it up then for sale or the PO took good care of it?

It 180° warm enough? I sure can tell how much better/quieter it runs at full temp compared to cold.

Thanks

DL1221

You're right hotter running engines are more efficient, but in the hot So-Cal summers, I really like my 180 thermostat. When I had the factory 190 it ran just like yours, and watching that needle go near the high mark really made me nervous. And that 180 is a factory Cummins part, so I'm not worried about the quality. . . anyway, good luck with your new truck.

Oh, by the way, are you watching your fuel pressure, you know about the lift pump problems these trucks had, and not to mention the VP44 issues too. . .

RowJ

Totally agree. The Cummins 180* T-Stat is far surerior. Does not have the quick warm up plate, that has broken off at least once to ruin an engine.
My 180* T-Stat sit there all day long and barley reaches 190* when working the engine very hard.

If I lived up north, I would swap between 180* & 190* every summer and winter! Down here, I threw the 190* away after two months of seeing the 180* in action.

RJ

Symon623

Thanks for the replies guys. I'll check into the 180° t-stat.

DL1221, yes I am definately watching fuel pressure on my Edge monitor, the LP was replaced with a carter unit, i know there are better ones, but it'll get me some time til I can afford one of the good ones.

RowJ

If interested.... 180* Cummins Part # is 3967195

Good Luck

RJ

Symon623

Thanks, where can I get one?

bnold

Local Cummins shop is the easiest...

klx650a2

Does Cummins make a 190?

Invader

Isn't the OEM one 190? That's where my needle sits and fluctuates around.

DL1221

Yup, the OEM thermostat is indeed a 190.