Overheating

Your thermostat will be located at the upper radiator hose where it enters the engine block. You may have to remove other components to access the housing for it to replace it. You may have a defective coolant temperature sensor or low coolant level causing your problem as well.

my 91 ran a bit higher that halfway up the gauge, check to see if your rad is blocked you can blow any debris out with compressed air or pressure washer but be sure to blow from the engine compartement out because the other way will only jam stuff farther in. if you have a/c check that the condenser isn't blocked because it sits right in front of the rad and will subsequently block that too, make sure your electric fan is still turning on if it isn't you may need to replace your thermoswitch or the fan itself, the thermostat is easy to check if you have a thermometer hang the thermostat in a pot of water so it doesn't touch the bottom and boil the water you should be able to see when the valve opens check the temp of the water when it opens and compare it to the specs which should be in a haynes manual or google them, good luck