isuso nn 2010 problem
 

Good afternoon, I have an Isuzu nn 2010 3.0 150cv I bought it new, I never had any problems, it has 177m km.. It recently started to heat up, the following symptom appears the car goes to 90 degrees as soon as I turn off the car the temperature does not always drop to zero, if it is at 0 the temperature goes to 90 degrees if it is 1/4 it rises to 110 degrees.. a thermostat was installed, checked the water pump.. shouldn't the temperature in the quadrant always return to 0 when the car is turned off?