Greetings - looking for some coolant system assistance

My '01 A8L w/ 4.2 (150K miles) has run at normal temp on dash gauge, for as long as I can remember, but lately creeping up, to 1 tick, sometimes 2 ticks beyond normal, then down, back up, etc.

I'm in Chicago temps which sees an fairly extreme reange outdoor temps - has no effect - same behavior yearound. Lately, I'll start in any outside temp conditions and gauge hits normal and stays there for short driving period. After 10 minute driving, in city or highway, summer or cold, it climbs as high 2 ticks past norm, but usually runs at 1 tick above norm....The only time I can influence temp is when I downshift and send RPMs up - temp gauge then goes down to normal, until I shift back in auto / Drive, then back up between 1-2 ticks w/ normal driving

My other observations:
I don't think stat has ever been replaced
No coolant leaking
I get normal heat in winter
I have NOT checked relays yet
If parked and idling, temp hangs at normal or slightly hotter
Aux fan kicks on only with AC ("econ switch off") - normal?

Help please....Any logic from this or what should I check first? next?

Thanks - GH62
Haven't checked relays or fuses

 

im having the same problem!! curious if its tstat not opening enough? any info will be appreciated

 

It sounds like the thermostat. There is plenty of info on this forum about it