Ok heres the scanario briefly...

LS4 with a 160* tstat installed...worked great up until i noticed once i switced to E85 my temp gauge would not register but maybe a lil above the bottom line...which on my scangauge shows 150's approx...

needle will fall on its face and not register when the temp still registered 170 or lower according to the scangauge... and then i will get a msg on my DIC screen of the car that says "A/C Power Off To Protect Engine" and my A/C will not work.....but my heat will?!?!

so im getting the opposite of a bad tstat staying open...and its def. not staying closed....

Now, if i reset the car by undoing the neg term from the battery and reconnect it...the gauge will pop back up and register...?? but its only a matter of time before it starts up again on the next drive cycle and starts to struggle to get to temp....

i do notice that even though im seeing a temp increase on the scangauge to like 170 or so while the mechanical isnt working...Its still not achieving the regular 174-188 i will see on a warm day while the gauge is working correctly....even with the 160* stat in and E85....which the 174 range is usually what a lot of guys see as a norm OT for LSx E85 cars with 160* tstats, from what ive observed...

It threw a DTC the other day indicating the engine was not able to get to optimum OT...I cleared it and went on...then the gauge sometimes will pop back up and my temps go back where they are supposed to...

coolant is where it is supposed to be and the right stuff...so dont go that low on me LOL...little past rookie on this one LOL...

but everything is going against itself here LOL...

some opinions would be great! thanks guys! and switching to a RWD or an Fbody doesnt count as an opinion! LMAO!!

P.S. im thinking its a combo of the block/coolant sensor and the tstat...is only thing i can really come up with..but its a brand new tstat...and a BIATCH to get to!!!