Coolant temperature

1999 Park Avenue recently changed thermostat from 195 to 185 Delco make. I thought the engine was overheating after observing the overflow container (coolant) overflowed.

The fans are coming on when the coolant info displays 210 degrees and temperature lowers to approx 205.

Is this normal when the temperature indicator is approx. mid-range and the info displays coolant 210 degrees F when engine is hot.

Thanks.....

If you observed the overflow occurring after the engine was shut off, that would be normal. The engine is still hot and the water isn't circulating.
The temperature readings of the your fans coming on sound normal. My temperature gauge ranges from 190-210 degrees while the engine is running.