I pulled the 160 t-stat to make sure its not stuck open and it's closed.
I have not checked the lower 143 t-stat to see if it's stuck open. [/quote]
I had to replace my impeller because the P.O. never checked it and it was pretty much torn up.
I want to check the hoses and the t-Stat, but after reading this, are there two T-Stats? I thought there is only one. this is a 5.7 Vortec Engine.