You may have air trapped in the system. Bleed the system. Also clean the external radiator fins. Check to see if water pump is functioning properly. You may need to have the system chemically flushed.
are you sure its not rusted? cause me 92 Plymouth acclaim's oil pan rusted, and i had to get a new one. it only cost like 3-$400.
Check lower control arm bushings.
Clogged fuel filter, or weak fuel pump.
could be your thermostat is stuck or perhaps and needs to be replaced.
The thermostat may be installed backwards
There must be a short in the system somewhere that causes the fuse to blow.
The Thermostat and Temp and Press Valve is faulty and needs to be replaced. or the PRV (pressure reducing valve) is dirty and must be replaced
Could be the TPS, it will cause it to idle high and low and make the car become sluggish, but a vehicle will run without one, but it will run very rough.
Sounds like blown head gasket.
the reason why the coolant is spilling up over the reservoir is because the thermostat needs to be replaced because when the engine needs water the thermostat heats up from the engine and causes the springs to expant which opens a seal to allow the water throughout the engine i just realpaced the thermostat in my volkswagen
Since you had to unplug the wire connector, there is most likely damage to the connector. Check it carefully.
There are a couple of reasons why a 1996 Cadillac Seville SLS may overheat. The coolant may be low or the thermostat needs to be replaced.