3rd thermostat, new, still swings....

[dvieira]

Hello

well on my 3rg thermostat, first one swung, 2nd bought at Dodge dealer, it held steady, but towing my 5'er up Hwy 80 to Reno, swung to about 220deg's

{transmission temp held good though}i was watching EGT's at 1150deg's, and then bought new thermostat at Cummins West,San Leandro, now it seings back & forth, i have a trip planned in 3 wks to San Diego, and if the temp's hold good over the Grape Vine, then i just wait till my next coolant change before i change out the thermostat.

any idea's why it seings

thanks... .....



dave vieira

97 Metallic Red

antioch,ca

 

[Jeff H]

Are looking for the t-stat the holds a steady temp? I ordered one last year and has worked good. Lot of people were giving me the wrong part # for this steady t-stat. If you wan't the part number I'll try to find it again. It was listed in a previous TDR book.

 

[HEMI®Dart]

dvieira,



The newest T-Stat thats not supposed to cycle is Cummins P # 3934373.



I put one in, and it still cycles, not as bad. Check your radiator cap. Make sure its holding pressure. I found when I put a new radiator cap on (Old one still held pressure, but leaked from the center rivet) most of the cycling stopped.

 

[dvieira]

stranger still.....



the thermostat in the truck now is part#3934373.

like you stated, and it swings, the thermostat i took out is from the local Dodge dealer, and it didn't swing but the temps got as high as around 220 deg's, but that may be normal hauling up Hwy 80, toward Reno, pulling a 11,000lb 5th wheel,

and that part # is 3928499, oh well thanks to both of you, i'll live with it till next year, another coolant change.

thanks again.

dave vieira

 

[sewman]

I put a 180 degree stat in for the 360 v8 Dodge engine doesn't cycle much like the original did & didn't cost much either. I reused the old seal. I think I should of maybe bought the higher temp though. Like a 192

 

[danandamy]

Not to be a smart *** or anything...

... . but I was wondering, why does it bother you that it swings? These engines are so effecient, they don't generally produce enough heat to make the thermostat stay continuously open, thus the cycling. As long as mine keeps cycling, I'm happy. It's when it quits cycling and steady climbs, that's when it's "uh oh" time.

 

[diesaldual]

you said it!!

Why worry about the up and downs?? It is when it keeps going that makes me worry!!

Mine has always ran at 140 then sweeps up to about 190 and after a few min. goes back to 140. .

I like it this way. At least you know it is doing its job... Make me fell better. .

 

[BPINE]

Hey Dave swinging between 140 and 190 is pretty normal but going to 220 is not. I would suggest trying another 3934373 that's the one I found to work the best. After the third one I finally have one that works pretty good.