I have a 1996 S10 which runs hot sometimes red lining. I have checked or changed every possible part or reason. any thoughts here??

Reads in the red ... could mean to high or low pressure.
Explain .................................................

In my case (1995 S10) it was as simple as the temperature control potentiometer. The pot contacts were crushed, God knows what breaks and shorts happened there. Replaced the pot and all works like a charm.

My first thought was fuel pressure. Low fuel pressure would cause the engine to go lean but not set a code for the actual problem.
Is it possible the fuel filter is clogged ? Have you checked fuel pressure?

not value cover gasket leak out around spark plug not to inside piston. but cut right off how hot? no water in oil? or filled up piston? maybe head crack. fuel pump pumping? crack line not went eng hot. ture key on look or someone look 10lb of pressure comeing out fast.water no. antifreeze yes.

Possible fan clutch..Usually if its a fan clutch it will run hot sitting still but cool off once going down the road..If it takes a while to run hott then i would suspect a clogged radiator..When you drain it did it look like all the antifreeze came out..Ive seen half the radiater clogged up where half of it drained but the clogged section stay in the radiator

Hello: Check and make sure the air mix door is in the A/C position, air mix door is sometimes called the blend door. If it is a manual system follow the cable that is connected to the lever that goes from red (hot) to blue (cold) see if it moves the door when you move the lever on the control.

Do you have the Northstar engine? If so, there is an issue with head bolts pulling threads. Clues are periodic overheating. Look for exhaust in the cooling system. What happens is under load the compression gases push coolant out, and then you get overheat.
Pressure test the cooling system, there is a small hose that runs from the engine to the coolant tank, sometimes that plugs and air gets trapped. Some models suffer water pump impeller failure, easy to check with a special removal tool.
The head bolt issue is EXTREMELY expensive to fix correctly. Essentially you need to time-sert the bolt holes, and to do that you need to give a bare block to the machine shop.... Real bummer as the repair typically exceeds what is reasonable to invest in the vehicle, thereby rendering the vehicle useless.
I did repair mine, because I really liked the car.This issue should not happen.

There could be some air still in the system...Sometimes when the head gasket starts to go it will put a small amount of combustion into the system...Hard to detect at first...A good test to see if this is happening is when the engine is cold and you start it up, rev the engine up for 30 seconds and then shut it off..Open up the system, if their is pressure present then the gasket is leaking...Caution..Do not do this if engine is warm...

check for loose or cracked vacuum lines, and/or the rotor. It may not be making consistant contact.

you can get the premade lines from chevrolet. not positive on your year model. but i know they have for newer models.