New T-stat bad?

[beemerbiker5]

When i did the coolant flush/swap/filter install, I also changed the t-stat as it seemed to be bad, never allowing the ECT to get above 186-188, unless pushed hard.
From the install, the new one did the same. How often does a new one come out of the box bad? What makes a t-stat fail in the first place?
I can replace it, again, but what if something is making them go bad?
Today I did an EOT/ECT check, 46*F ambient, 65mph, ECT 186-188, EOT 194.
Another new t-stat?

[dhanna6powerstroke]

Originally Posted by beemerbiker5

When i did the coolant flush/swap/filter install, I also changed the t-stat as it seemed to be bad, never allowing the ECT to get above 186-188, unless pushed hard.
From the install, the new one did the same. How often does a new one come out of the box bad? What makes a t-stat fail in the first place?
I can replace it, again, but what if something is making them go bad?
Today I did an EOT/ECT check, 46*F ambient, 65mph, ECT 186-188, EOT 194.
Another new t-stat?

It's good. Mine reads about the same with a new t-stat.

[F250SixOH]

Originally Posted by dhanna6powerstroke

It's good. Mine reads about the same with a new t-stat.

X2. Just put my t-stat in last week and it stays 186-190

[Gearhead2012]

Ditto, mine are identical also.

[beemerbiker5]

Thanks, guys, what I thought, too. But, reading here just made me think otherwise. Seems the norm is between 190-194.