If your Pathfinder is over heating then you may have an issue with the coolant. You can try adding more coolant to ensure that your car is no longer over heating. You can also double check to make sure your blower is actually cooling your engine.
If the coolant reservoir can not maintain the proper level of coolant, it is possible the engine could over heat when the level drops.
Have you checked the coolant levels or the cooling fan?
Can result in freezing in the winter and over-heating in the summer.
try taking out the thermostat and have you put to much oil and coolant in the radiator
it can be many stuff but in your place i would check first the coolant level and the thermostat
You could possibly have a circulation problem, or a over heating problem. Need more info.
check your coolant if it low refill it. check your coolant bottle and radiator for leaks if all is still over heating..sell it you have blown heads
Just because there is a leak doesn't mean it will overheat instantly, but if you do not keep adding coolant or fix the leak you will have engine problem
Check the coolant level and make sure that its full, and is not leaking down over time. If the system is full then the low coolant sensor is probably bad.
This would indicate that the system is low on coolant when the gauge is hot. Not enough coolant to service the heater core.
Stuck closed thermostat, cracked head, bad head gasket, low on coolant are some possiblities.