Never open wallet till problem is diagnosed thoroughly. Early spring maintenance on a 2001 Ram 2500 5.9 v8 re46. Oil change and filter, and decided that I "THOUGHT" that the thermostat was staying open too long.
Relied on the dash gauge . DID NOT measure temperature at the thermostat housing first. Did a flush and replaced the thermostat with what I thought was a Hecho el los estados unidos , as it said so on the box Gates 195 degree thermostat.
The gates looked inferior to the one removed that had a metric size on it . This was when Benz ran the show. New thermostat reads colder at the temp gauge and the temp at the housing is 165F.
I was attempting to get the temp up in an effort to improve mpg. I will probably go back to the old thermostat.
Gosh dang darn dangnabbit.

 

Maybe run it for a bit and see what the mpg actually are. Not doing things on a hunch again but with hard data ....

 

The plan. Run up to NAPA with new thermostat in engine. Get new gasket. Check temp with two thermometers at radiator neck at end of trip Snap pic of gauge readings.
If unacceptable drain down cooling system remove thermostat.
Put both thermostats in a pot of water suspended from bottom, watch the Temp rise and see when they open.

If you have a better idea please advise.The box said Made in USA, but no USA stamp on the thermostat. Reading an earlier post I think I may have been had and it is a motorod in a Gates box.

 

Did you get a low temp code? Hook up a scanner to see what temp the pcm is seeing? T stats with out a bleed valve or drilling a hole in them trap air. If it has air you will get a incorrect reading. Check out post #14 here.

 

The scan tool idea was good whiskey, thanks. Will do first drive of the am. That looks like a Toyota thermostat.

 

Plugged in the Scan tool that was gifted to me by a friend. Runs in the 185F range, going as low as 181 and as high as 189.
After searching the forum it seems that my hunch was correct.Running colder. The Gates I received looks just like a motor rad. I will go back
in and replace the bypass hose while I am there and reinstall the old stat.
The Truck is a pig on gas getting 10 mpg in 2/3 around town and one third highway. 2wd with maybe 300 lbs of load all the time.
I have a nonstock el cheapo muffler on it, and I don't know how much that hurts.
I will post some pictures of the two stats when the gasket and hose come in.

 

Muffler simply doesn't matter. At least, not enough that you would notice a difference. How old are your O2 sensors??

 

I have never changed them. Truck has under 82 k miles. They could be old enough to buy liquor. I've had the truck for four years and haven't put ten thousand miles on it and a redone trans. .You were very helpful in getting the transmission straightened out and if I haven't thanked you, thanks now. It's just annoying to put 30 gals in every three hundred miles. Fuel trims are reasonable, and the truck runs a round with a ladder on a rack on it all the time so I guess that's what it is.
I went the stainless steel line kit when I first got it due to the poor quality of the lines that had been replaced by the original owners. Did calipers, rotors drums wheel cylinders and shoes. 88oo lb lb trucks on e range tires ride hard empty.
I have a short bed 94 GMC 1500 4.3 five spd, dead for 8 years that will be my daily come spring.
NAPA offers Bosch, Denso and NGK sensors. I have had similar experiences will all in other vehicles, but are Dodges finicky?

 

Please use the NGK/NTK O2 sensors. Dodge trucks are real finicky when others are used.

 

The NGK/ NTK Amazon store is legit? Thanks for the heads up. Mopar 56041943AA NGK 23139 is the upstream?