It takes a special socket and it will unthread counterclockwise. Use of pliers may damage the sending unit.
If that S10 has a 4.3 engine, I find it best to remove the distributor to gain better access to the oil pressure sensor.
knock sensor
If it is a 1997 S10 4.3, with the engine running, remove the fuel pump relay, if the engines stops running, the oil pressure sensor is bad.
it is under the distributor.
Remove the tail gate then replace water temperature sensor.
It is not an oil level sensor it is an oil pressure sensor. It just unscrews.
To remove the speed sensor on a 1999 Chevrolet S10, first, ensure the vehicle is parked on a level surface and the ignition is off. Locate the speed sensor, which is typically found on the transmission or transfer case. Disconnect the electrical connector by pressing the tab and pulling it off. Finally, use a socket or wrench to unscrew the sensor from its housing and remove it from the vehicle.
Locate the crank sensor behind the vibration damper (crankshaft pulley). Unplug the wire harness connected to it. Remove the small bolt holding the sensor in place. Remove the sensor.
To drain the oil on a 1991 Chevy S10 Blazer, located the oil pan drain plug. Use a wrench to remove the plug and the oil will flow into the receptacle you have provided.
It is about 3 inches long with an electrical connector on the end of it. It is back by the right hand side of the distributor. Hard to see.
The 1994 S10 uses a MAP sensor, not a MAF sensor. We need to know size engine you have in that S10.
Drain oil from oil pan, remove oil filter through access door unde raditator.