OK if its not a gasket.. Then what the heck is it?

[David Omalley]

Ok I know it's a stupid question but I got a new themostat from Cummins. And it came with a plastic gasket.. Which is clearly labeled NOT A GASKET.. It will clearly fit between lift hook and inlet. Doesn't look like it will hurt anything.. should I coat it in rtv? install it as is. Or throw it in the trash. .. and what is it? Cause if there was one in the assembly originally it definitely disintegrated.
Thanks Dave

 

[David Omalley]

Maybe this will help.

 

[Daw14]

Why would it be labeled top if it wasn’t something that you should use? That is odd . Maybe a diesel tech will enlighten us.

 

[Dennis Shellito]

You haven't stated what year/engine you are referring to, or any other identifying info. I thought all 6.7L Cummins used an o-ring to seal the Tstat. The "gasket" you have pictured is a Tstat gasket, but what application, I have no idea.

 

[David Omalley]

I'm sorry. You are right. It's a 97 5.9 L ..
Here

 

[Treburkulosis]

@David Omalley This shows to be it. https://www.autozone.com/gaskets/th...VFKjICh137w1REAQYBSABEgKTgvD_BwE&gclsrc=aw.ds

Id trash it and go get a felpro gasket.

 

[David Omalley]

Yeah I'm gonna make one up and just send it. It's a genuine cummins thermostat so at worst it gets stuck open and try again. I'm not quite sure if it's even the right one. This engine is new to me as Is the whole diesel thing. But I'll get there I promise.
Thanks so much for the help.. I'll keep u informed of how it goes

 

[Scottly]

It's NOT a gasket. It is a template to ensure the thermostat opening is the correct size and shape, as there is a TSB out there detailing thermostats that didn't function correctly due to them binding in the head.