Hey guys I need help. Last night my car overheated. Pumped all the water from the expantion tank but not the radiator{tank with pressure cap} could it be fan not going on or thermastat not opening up.????? Any ideas? Have not looked at it yet  Thanks 

If barfing out your overflow tank, I would suspect the thermostat is stuck.

It had to have lost some coolant from the radiator is it puked it all out of the reservoir.
What did your temp gauge show?
Could be the fan(s) not coming on, for several reasons, so I would start there. The main fan should come on around 220 or so, or both fans should come on with the A/C on....assuming the A/C works.

Yes both fans work fine Ac blows cold even heat I think the thermostat is sticking . When changing it I do have to be carefull not to get the opti  wet is that right ?? Any sugestions ??              If I need a thermostat what should I go with 160 190??

|UPDATED|5/2/2013 7:14:47 PM (AZT)|/UPDATED|

Could well be a stuck thermostat. Only one way to be sure! DEFINITELY wanna keep any coolant from getting around the Opti. Best bet is to drain the radiator first. This will lower the coolant level enough that you shouldn't get much more than a dribble from the housing when you pull the t-stat.. I would put some plastic over the top of the popti first, then a towel/rags on top of that.
I would also suggest staying with the same temp rating stat as what's in there now. Lowering the opening temp doesn't actually make the engine run cooler....it just opens the stat sooner. Once the engine gets to operating temp, the stat is really nothing more than an orifice in the cooling system.

How long did it run before both hoses were hot? If only a few minutes, you may have a t-stat stuck open, or someone has left the t-stat out completely, which is not good on the LT1.
By all means use the bleeder valve to purge any air, but be careful, as any coolant leaving the bleeder will drain right on top of....you guessed it....the Optispark!

Joel can I get to the bleeder with the intake on ? I took it off also mas flo and looks easy don't know if I can get it when hooked back up> Car is in another storage garge so not near me now Will look in the morning No work on Sunday Ha Ha

|UPDATED|5/5/2013 5:45:26 PM (AZT)|/UPDATED|

The LT-1/LT-4 engines can be bled with everything in place...just be sure to protect the Opti.
Open bleed valves on thermostat housing and throttle body(#2s in pic) prior to adding coolant. Add coolant through radiator surge tank opening until level is at base of tank neck. Close each bleed valve as solid flow of coolant is emitted from valve. Start engine and operate with surge tank cap removed until engine coolant level is maintained at base of surge tank neck. Add coolant as necessary, then install surge tank cap with arrows facing overflow tube. Fill coolant recovery reservoir to proper level. Start engine and allow it to reach operating temperature. Turn engine off and allow to cool, then recheck coolant level.