Engine/Transmission (1994 - 1998) new thermostat still not coming to temp

[McCoyJ]

I have a 94 ram 3500 2wd 12 valve manual and its been running not to far past 140 since i;ve gotten to arizona from indiana. I changed the thermostat today and the gauge is moving just a little bit more , but its not doing the usual go to 190 then back down then back to 190. The thermostat is from napa. Any suggestions. This is my first deisel

 

[Howard Durand]

The fan is thermally controlled. Maybe it is not functioning properly. Mine is doing about the same thing. It fluctuates between 140 and about 160 and sounds like the fan is running more than usual.

 

[K5IP]

I think these thermostats tend to run on the cool side. I went through three of them )from Dodge) before I found one that would not fluctuate, and yet run as warm as it should.

If you had one that actually ran at a normal temperature, but fluctuated, you might want to do a search on thermostats. A previous post talked (and showed) how to drill a small hole in the thermostat, bypassing a small ammount of coolant, and eliminating the fluctuation.

 

[Joe G.]

If it is NOT fluctuating something is wrong. When mine stopped doing that the engine was running too cool. I found that the rubber around it had slipped and it was jammed open a little bit. I got a new one from NAPA. It is fluctuating again and running much warmer. The only way to stop the fluctuation is to make the stat leak a little. Drilling a hole will do that, but you need a better coat in the winter.

 

[bgilbert]

NAPA t-stats are known junk. Get yourself a stat from Cummins.

 

[CumminsPower98]

My original worked great until the rubber came off and jambed it open. I got the replacement from Cummins and it runs pretty steady. I would stay away from any aftermarket ones. Go to Cummins for this part and you will probably have better luck.

 

[McCoyJ]

yea i wish i would have gotten it from the cummins dealer, but i needed one fast didnt know the area and bought that one because i seen a napa. better than autozone in my opinion. I will look up a cummins dealer and buy one and replace it when i get back to indiana. thanks guys

 

[Joe G.]

yea i wish i would have gotten it from the cummins dealer, but i needed one fast didnt know the area and bought that one because i seen a napa.

Same here. No Cummins shop in Green, OR. There is a NAPA store close by in Winston so I got one there. It has worked just fine so far. If it gives me any trouble I'll get one from Cummins here in Humboldt County.