Thermostat Early Warning Sign? Or Something Else?

[spooltime]

In my six months of daily driving my CTTS, the water temperature gauge needle always rises up at full operating tempature to pointing just short of the 180 degree indicator (at the 12:00 position on the gauge), and then basically just stays there without fluctuating.

While driving into work this morning, I noticed the needle rise above the 180 mark (to about the 12:03 position if it were a clock) and then drop back to the 180 mark. It did this several times, raising my concern.

I get that there will be some fluctuation, but the movement this morning was out of the ordinary for my gauge's normal behavior. It makes me wonder if the thermostat is beginning to stick a little bit, or if maybe one of the fans isn't working the way it should. The vehicle has just over 78K miles on it, so I'm wondering: i) what the normal life expectancy is on the thermostat; and ii) whether it makes sense to do a preventative replacement of the thermostat now rather than waiting until it fully goes and getting myself stranded somewhere? FWIW, the engine already had the coolant pipe update done before I purchased the vehicle.

Any insight or thoughts appreciated.

[JFP in PA]

It may be the beginning of the end for the thermostat, which by-the-by is a "maintenance" item that needs to be changed from time to time, like the water pump. While most tend to wait until it fails (often either stranding them or potentially doing damage to the engine), periodic change out every 5-6 years, or when doing either the water pump or freshening the coolant would be excellent preventative steps. These things never crap out at a convenient time or place, usually choosing something like Christmas Eve at 11:30PM to die.....

[mcbit500]

The first summer I had my 05 CTT (Dubai/ Abu Dhabi 45+ deg C) it behaved normally as you described. The following summer it the needle started wandering up to the 3/4 mark on high speed or high boost driving. It continued to do this for the next 2 years which I owned and continues to do so with the new owner (a friend of mine). According to Porsche this is within the acceptable operating limits for the engine, in fact they go as far as to say that it is acceptable for the needle to go into the red provided that it comes down again when you reduce engine load.

One more thing which I noticed was that when I replaced the battery prior to passing on to the new owner, it damped the speed and amplitude of the temperature fluctuations so possibly a voltage influence also.