My 01S has a low temperature thermostat. It runs at or to the left of the black hash mark at 180 on the dial. If I sit in traffic, the temperature might creep up to the left side of the 0 in 180.
I'd guess several possibilities given your description of high temperature operation.
- If you've recently changed your coolant, perhaps there is an air bubble in the system that restricts flow. Search the forum for the proper way to burp it.
- Your thermostat might not be opening fully.
- Your water pump may have broken impeller blades whereby the coolant isn't circulating properly.
How many miles do you have on the car since the water pump was last changed. If its over 60,000, you might want to replace it. My recommendation is to replace it with the Porsche OEM part. While you're in there, put a 160 degree (low temperature) thermostat in.
Take care of this soon. These engines don't like high temperatures.
Hope this helps