Engine/Transmission (1998.5 - 2002) Found rubber gasket in thermostat, where's it from?

[MRose]

Thermostat stuck open after so heavy towing last weekend so I got the new updated one from cummins, (part number had been updated 5 times) and popped the old one out. Had a rubber gasket the I can only best describe as looking slightly like a valve stem seal, 2inches across with a . 5" hole, dished slightly. Ring a bell? Also the old t-stat looked like it would be a much better flowing design, much larger opening. Are there high flow t-stats made for us? Thanks guys.

 

[B.G. Smith]

Sounds like part of the thermostat, it fit over the dome on the valve part of the thermostat.

 

[MRose]

??? Really, never saw one with it. New one dosen't nor any others I've ever done but this was my first cummins t-stat. Just wanted to make sure I should not be worried.

 

[SnoKing]

How about from the Radiator cap??? SNOKING

 

[B.G. Smith]

??? Really, never saw one with it. New one dosen't nor any others I've ever done but this was my first cummins t-stat. Just wanted to make sure I should not be worried.

I have changed mine three times and they all had the rubber seal in the center, a cone shaped piece. The first one, the rubber thing came loose, the second , one side of the yoke broke. Third just didn't act right. I haven't bought one in a few years, maybe they changed the design. I still have a spare one under the rear seat and it has the rubber too. bg