Just bought my 1996 altima. The car is running very hot. I have replaced the radiator, water pump, coolant temp. sensor, and themostat. For some reason the thermostat does not appear to be opening. So I thought it might be a bad thermostat, and replaced it again with the same results. My question is what would cause it not to open, or why would the car still run hot after I replaced almost everything that has to do with cooling? It is not showing any signs of it being the head gasket either.

SOURCE: 92'Sentra GA16 suspect cooling sytem failure

you my friend have a blown headgasket, and heres why #1 you have white smoke at start up(this is an indicator of water in the fuel and hence through the exaust when it mixes in the cylinder#2 it goes away after the warm up(this generally happens because the cylinder is so much hot than the boil point of the coolant)very little smoke would be noticed#3 oil on a plug(if they were all of the plugs i would say you had bad valve seals or oil rings on pistons) seeing that it's only one pretty much tells me that is where the gasket is leaking.#4 poor idle(car will idle rough and hesitate because the computer is trying to compensate for the water air fuel mixture. hope this helps please rate this

SOURCE: running hot

Radiator Fan Control Relay Switch. I bet your electric fan doesn't run?

SOURCE: I have a Nissan Patrol Y60 TD42. It overheats

sounds like something clogged in the block its self try to find an acid flush and flush the system a few times untill it comes out clean

SOURCE: I have a 94 nissan altima that overheats. I

sounds like where the water pump meets the engine has warped or the gasket has been blown. Since the water pump has to come out anyway to fix it then i would suggest replacing the pump. It is 30 to 40 more.

SOURCE: 1996 nissan altima running hot changed thermostat

check the operation of the fans, since the radiator was recently replaced, it is posible they may not be plugged in correctly or operating like they should, if they look good, look into the water pump, with the work that u already did the only this left to look at after the water pump is the intake or head gasket, any water in oil or vice versa? look into that if all else fails....