I just bought an 88 integra, on the way home I noticed it was running pretty hot the needle a little more than 3/4 the whole way home, I am wondering how I can check my fan to be sure it works. Should it always be on when the car is running?

 

The fan is not always supposed to be on. The fan is controlled by a normally open thermo switch. When coolant temp gets to 190 the thermo switch closes and energizes the fan.
To test the fan apply 12v to it. Or you can use continuity check if you got an ohmmeter.

 

fan thermo switch is at the thermostat houseing

if u by pass it with the key on on
the fan should run