2nd Gen Non-Engine/Transmission Do I need a new thermostat?

[bbradford]

I just purchased my "new" 1997 a few weeks ago in Texas and drove it back to Tennessee. The temperature never got above approximately 160 degrees, even on the long interstate drive. Everything else is normal. (Except the dead fuel gauge, of course. ) On several TDR posts I have read that the normal operating temp is for the CTD 190 degrees.



Do I need to change my thermostat and raise the temp to 190? Is operating at 160 good or bad for the CTD?



Thanks,



Ben



1997 3500 clubcab, Laramie SLT, leather, auto, stock (KDP tabbed) 101,000 mi

 

[WDaniels]

bbradford,

If the thermostat has been replaced already, it is probably a 160 if memory serves me correct. Operating at 160 isn't a problem if you are not in a cold climate and want heat. I don't think you can get a 190 thermostat for the cummins like the one that comes stock. You can get 190's for them but they are made for gas engines, but work well with the diesel. I have them and they do throw heat but will heat up to about 205 before opening and operating properly.

WD

 

[FourBarR]

just bought a 180 f from cummins. had an oem of 190.

 

[WestTN]

!60 is a little cool. It might allow the engine to carbon up unless run HARD.

 

[bmoeller]

You can get a 190* OEM stat. I got one from the dealer, and was in a Cummins box. Had the Dodge sticker over it.

 

[WDaniels]

I stand corrected.

WD

 

[bbradford]

Thanks guys. All the conventional visdom seems to say that I would be better off with a 180 or 190. I'm headed to the dealer today to see what they have.



BB

 

[JJW_ND]

12V only have one TStat

The thermostat and its affect on the engine is alot different between a 12V (What Ben has) and a 24V. Coolant regulation in 24Vs seems to be much more stable and warmer. There is options in TStats in 24Vs. There is only one Tstat for the 12V (3934373 is the Cummins part #). It was very common in 12V to have the coolant temp bounce endlessly from 140 - 180. Cummins came out with this revised TStat that fixed the cycling but the trade off it runs cooler. Your 160 degrees sounds about right. That is were my 96 runs. I believe the gauge reads just alittle cool on these 12V. The real temp might be alittle warmer then what the gauge shows. While I would love to have the temp run at a constant 190 (better economy) but I like that the temps do not cycle.



Ben, if you want to try a different TStat, make sure you get one for our 12Vs.



I have always ran Cummins Tstats but picked up a NAPA (part # 370-180) to see how it runs as I need to go a coolant flush.



jjw

ND

 

[bmoeller]

I have always ran Cummins Tstats but picked up a NAPA (part # 370-180) to see how it runs as I need to go a coolant flush.



jjw

ND

If it is a Gates stat, it'll probably be all over the place. Mine was.

 

[K5IP]

I just replaced the stat on my 95 to fix fluctuation problems.

The first one ran cool (about 160), but did not oscillate. The second one runs about 175 with only very minor changes (+-5deg).

I think operation at 160 is pretty common from what I hear, but these things really need warm up, especially for the best economy.

Rog

 

[bbradford]

Hi guys,



Thanks for all the great information. I got my new tstat put in today. It was a #3934373 Cummins part from the dealer. It didn't have a degree marking on it. (The idiot at the parts counter had no idea about what temp it was, or about life in general for that matter. ) The one that I removed, which had a different number, wasn't marked either. The new one cycles from 150 to 185. I assume it's a 180 or 190. The old tstat pegged at 160 and stayed there. I'll keep it just in case I can't stand the cyclying.



I don't know if I'm better off or not. Tstat-$39, new seal-$6, installation-$35



Anyway, thanks to everyone who took the time to write.



Ben