Water pump is the next on my DIY list.
However the fact that temp goes down when fans start means water pump is working.

Also end of 0 in 180 is equal to 105 degrees celsius in my car, and when the needle is at 180 mark is shows 83C on AC display, so the needle is fairly accurate.

Mine also never gets past 0 in 180, even when I was sitting in 100deg weather (last summer) in traffic with AC ON for almost 1hr (520 bridge in Seattle is famous for that..)

But you're right.. the car is 11yo, water pump should be changed along with low temp thermostat.

Thanks
Sasha