Ok, I have searched this topic and all I can find is "remove thermostat"

I have a 1994 240sx STOCK EVERYTHING....When I bought the car it ran very hot, So I started from the what I noticed was bad, Fan shroud was messed up, REPLACED...
Still ran hot, Then I just said the hell with it and replaced the radiator and cap with a known good unit, Still ran hot....
Looked up on TR and it said that KA's thermostats suck and to just take it out...When I dug in there to get it I Replaced the cracked Clutch fan and Noticed there was NO thermostat already....so I added one...and now it overheats so damn fast its not even funny....like it gets mid way on the heat index sits there for a minute and you look away and look back and its at the "H".... Now The last thing I can think of is water pump...MAYBE theres something on the KA motors that gets stock or plugged up before I tear out a possible good water pump...Just asking advice.
Jeff --- Dave any thoughts....