my car is having overheat problem now.
when the car is moving, the temperature is normal (around 90 degree); but when it stops (waiting for traffic light or jam), it will keep increasing (>100 degree).

mileage is around 75K, has changed the coolant at 60K major service.

went to SC on yesterday, they keep pressing the accelerate at N gear, but the temperature won't increase.
checked that, the water tank has enough coolant/water, and the fan is working fine.
they have no time to do further checking due to there are too many cars are doing the car service.
they advised me to come at weekdays and do another checking, probably need to wash the water tank.

my question is, i suspected maybe the hose stuck, can it be fixed by washing the water tank?