1996 S320

I recently had the water pump and thermostat replaced on my 1996 S320 when the coolant began serioulsy leaking from the pump. The dashboard temperature guage read at 80 or below but never over 100 prior to this replacement and now reads at over 80, often at or exceeding 100 andn sometimes near 120 but never in red zone. What temperature reading should I see if my cooling system is working properly (I understand that temperature at idle is generally lower than when car is in drive and generally higher when air conditioning is running)?

You may contact me at tannj2@comcast.net if you wish to discuss privately. I appreciate all replies. Thx!

Joe