well, i had a problem a while ago with overheating and found my fans wouldn't turn on, i got it fixed but lately started overheating again. With radiator cap opened and revving the motor i can see movement of coolant so water pump should be working. When it got to 240 i checked and both fans were working but i noticed there wasn't much fluid in overflow tank. I went ahead and slightly popped the radiator cap(it's one of those safety ones that don't open all the way with first turn) and boiling fluid immediately filled the overflow tank.Could it be that thermostat is stuck closed or clogged radiator.
it's 89 firebird with 305 TPI dual electric fans