Coolant Temp. Light Slow Blink

[Hugh D]

Hey guys... I posted this on another forum recently but have no reply yet...

Let me first make you aware that I have done a lot of searching on this forum and others on this topic. I just wanted to gauge some extra input as what I have found has not fixed my small problem yet.

Here's what I have:
1998 Boxster
53,000 miles
Tiptronic
Ocean Blue
Hard top (because of this the cloth top is in brand-new condition... pristine)
On-board computer
CD Changer
Only had one owner... in Houston the whole time (no maintenance records, unfortunetely)

I have driven it about 200 miles since I bought it (it's a weekend car). The thing runs beautifully. The place I bought it from put a new battery and new alternator in as part of the deal for me. I have no complaints. The engine sounds beautiful!

Here's the problem:
When it is above 75F outside and I have been driving stop and go or I get off the freeway after a nice little run, I get the slow blink light on the temperature gauge. I am aware the slow blink means coolant and/or engine compartment overheat/fan. I used the diagnostic tool in the AC unit to find the exact coolant temperature... the highest I have seen is 101C/214F, which is just on the "0" in 180 in the gauge. So, the engine isn't heating up too bad, but I feel it is running too hot for the tempreatures outside not being much above 80F here in Houston right now. The light never blinks and the needle stays in between the "8" and the "0" in 180 if it is 70F outside and I dont do any hard driving. From what I can tell, having the AC or Heater blowing does not affect the temp or light at all. If I am on the freeway on warm weather the temp says just slightly above the middle of 8 and 0. If I get off and let it idle for even 10 minutes it only raises just a little above that... never to the edge or right of the 0.

Here's what I have checked/done:
1) I cleaned the front radiators of debris; 2) replaced coolant tank cap with the newer "01" part; 3) checked coolant level while engine was hot and cold (fine both times); 4) verified all fuses are ok; 5) verified that both front fans and rear fan are all 3 blowing; 6) pulled up rear carpet and looked around for coolant leaks... did not find any

So, do any of you have any insight as to what this could be? A sensor maybe? I definetely think heat has something to do with it because it only comes on in warmer weather or when I get the engine going pretty well. I don't think coolant level/loss is the problem. Could the compartment fan be going bad?

Here's the other thing: I'm not sure what kind of coolant is in the car, but I plan on getting it flushed soon because I don't know what kind (it's green... very clean). If it were not "Porsche approved" could it be causing the light even with no cooling/level issues?

Thanks sooooo much!