Next step after this would be to replace the radiator pressure cap, check ALL hoses for deterioration and leaks, check the coolant resevior bottle for leaks, and all connections to it. Check the drain plug and make sure it's snug in the bottom of radiator. Also, you may need a new water pump. Good Luck! I agree about the water pump, even if it seems as if it is working it will give poor circulation and cause overheating when pressurized until the bearings finally go out completely. but check the pressure cap first it is the most obvious and cheapest option, if it is bad when the system builds pressure and heat it will allow coolant to pass freely into the reservoir, but not draw it back in.
it could be the water pump or a blown head gasket
If you replaced some of theses already ignore and go down the line # Not enough coolant # Water pump drivebelt defective or out of adjustment # Radiator core blocked or grille restricted # Thermostat faulty # Electric cooling fans blades broken or cracked # Radiator cap not maintaining proper pressure # Ignition timing incorrect
Ingeneral, the fan will run only if the temperature of the radiator is above the normal range. If the fan is running, then the radiator must be over temp unless the radiator fan thermostat or it's relay is defective. If the radiator truly is over temp then you have a larger over-heating problem You state the thermostat was replaced. if you replaced the fan thermostat then either the radiator really is over temp and it is doing what it should, or there is a problem with the thermostat-fan relay or switch. If you replaced the engine thermostat that controls the flow of coolent between the engine and the radiator, then that probably wasn't your problem and you should look elsewhere for an overheating cause. I would start by determining if the engine actually is overheating or not. If it is, I would look for coolent system problems like the engine thermostat (if you didn't replace it already), water pump, leaks, scale build up in the radiator, or blockages in the system. If the engine isn't overheating then I would consentrate on the fan, fan thermostat and relays.
Maybe cooling line is plugged or crimped Maybe cooling tank in radiator is plugged Install auxilliary transmission cooler
Even though you have already replaced the thermostat, there are other issues that can cause your Nissan Maxima to overheat. Your fan may be stuck and not operating as it should.
Start by replacing the radiator cap, it is more dangerous than the thermostat because it loses pressure.
The radiator may be plugged. Take it to a radiator shop.
This may mean there is a weak hose OR some sort of blockage in the radiator or cooling system.
water pump. thermostat.
if your thermostat was bad your engine will over heat but it has nothing to do with the fan,fans are driven by a diffrent mechanism. try checking your thermostatic switch/ heat sensitive switch or sensor, located somewhere in the cooling system(radiator,engine block or thermostat housing) which is the one that tells the fan when to come on.(only electric fans)it may be faulty wiring
You could have a bad water pump causing no coolant flow, inoperable radiator fans, a coolant leak,............
I have already replaced the radfiator,cap,thermostat and confirmed water pump works. cools fine w/o radiator cap ,pressure builds and temp. rises when cap in place.