Mike Perez

I have a friend who has a 2000 dodge diesel 2wd. His operating temp is always 190 degrees, I have a 1999 4x4 Dodge diesel and mine runs cooler , right on the line after 140 and before 190.

Nappa said that the thermostat dosn't open till 190, does this sound right? Is his truck running too hot , or is mine to cold?

torquefan

I think there is enough variance between the vague factory gauges that this is not a concern. Make sure there is no large fluctuation in temperature, and as long as both trucks put out decent heat in the winter, and don't overheat pulling a big load on a hot day, all is well.

Buckshotmckee

Mine runs between the 180-190 mark all the time. In the summer time towin across the desert, 110-118 degrees, a/c runnin it stays the same. When I start pullin a grade it will get a little above the 190 mark, where the T-stat opens, and he sits right there.

Hemi Cat

If you just put in a new T-stat and the temp guage reads the same, I would guess that it is guage inaccuracy. If it bothers you try replacing the sending unit first and if the same replace the guage. Not sure on your truck but many electric guages have a resistor accross the terms and will fail.

Mopar1973man

Mine will pass the 190*F mark about a needle width and then the T-stat will open and drop below 190*F but it will return to the 190*F and sit there.

Mine was sticking on the closed end it would open with a snap. Rise really high 220-230*F then fall all the way down to 150*F and start over. This is a sign of a bad T-Stat for sure...

There was a discussion about this. I would say that the T-stat is sticking open and not closing until very cold. The owner replace the T-stat and the problem was solved! T-Stat's are cheap try a new one.

RustyJC

Ever since it was new, my truck has run a needle's width below the 190*F mark when running empty and a needle's width over the 190*F mark when towing our 5th wheel. If you're running at the first mark at the left end of the white line (normal operating range), it sounds like the thermostat is stuck open if the gauge is working OK.

Rusty

juicedcummins

The 99's had a 180 t-stat and the newer one run a 190 t-stat. I;m not sure when they swithched over.

Mike Perez

Thanks for all the info, My truck - the 1999 dodge - has reached 190* once, that was with my cab-over fully loaded, going up a grade in Baja. So I'll check my T-stat.

My friend - the 2000 Dodge - feels better about his 190* temp.

Thanks for all of your replies

MP

jethroish

Just got to the motel after 650 miles today. The entire trip, the dash gauge would drop to about 195*, then got up to about 210* before coming back down. No trailer, nothing in the truck bed, 3 passengers inside. Truck has not shown below 190* since long time. It has almost always shown 195*
Going to pressure wash rad. and all. Push come to shove, I got my tools with me, I'll change it or just remove it until I get home in 3 days. I'm gonna put in a 180* if I can find one easy enough.

RowJ

Get it from Cummins Parts Dept... PN #3967195
Love mine! Solved all my warm to hot coolant conditions when heavy... in the dessert, the mountains and at the drag strip... due to extra fueling!

RJ