Nissan Repair: Over Heating Problem w/ 1999 Quest, radiator fan, nissan quest

Question
I have a 1999 Nissan Quest that over heats when car is idling or moving slow while in traffic. It doesn't matter whether air conditioning is on or off. Radiator fan does work. I just replaced all 3 relay sensors as well. Need help! Could it be the thermostat? Car does not overheat while running on highway only while its not moving.

Answer
Alex,

Yes, I would look at replacement of the thermostat first.  Also, if the waterpump weap hole is leaking antifreeze it would lead me to replace that too since, at idle, pressure leaks off and there is not enough airflow to keep the engine cool, with reduced pressure.