2nd Gen Non-Engine/Transmission Thermostat Gasket Oddness

[Matt42]

I just changed the t-stat, and then reassembled it according to the diagram in the Dodge TSM. The t-stat uses two rubber gaskets, a thin one and a larger sleeve affair with a shoulder. The diagram in the TSM looked wrong, counterintuitive, and so on. It shows the smaller-diameter shoulder pointing toward the t-stat housing. Not thinking that could possibly be right, I checked the green Cummins glove-box maintenance guide. It showed the same orientation. So I installed it that way, strange as it seemed. It was a tight fit, which I suppose is intentional.



Did I do this right? I checked the archives, but I didn't find anything specific. I couldn't put it back the way I found it because it fell out on the ground when I opened it.



These shoulder issues always plague me. One of the best sets of piston rings I ever used had to be installed with the shoulder opposite to the way the rings were installed at OEM.

 

[bmoeller]

Wish I could remember for sure how I put mine in. (Put in new t-stat Fri. , too. ) I THINK I put the inner seal in with it facing the opposite direction from what is shown in the TSB. No leaks.

 

[Matt42]

Bouncing NAPA T-Stat

So I installed a NAPA thermostat because the OEM thermostat caused noticeable but not bizarre temperature fluctuation. The NAPA t-stat gives the temperature gauge St. Vitus Dance!



It's back to the Cummins dealer for me. Yeesh.

 

[bmoeller]

I doubt it will go away given that the sender is in the head. Common thing with these trucks. My new 180* (Cummins p/n 3928499) still does it. It is more active than the Stant 190* I had before at times. Sometimes it is rock steady. Kinda weird.