[PinotDino]

Originally Posted by Dmitry at Pelican Parts

Hello and welcome to the forum! wilnj gave you some great advice to help eliminate the possible issue. From your description, it sounds like the thermostat is faulty. There could also be an air pocket from when the coolant was serviced, which could cause those temp. fluctuations. If you have a scan tool, you can plug it in and see live readings of the temp. In case it is the thermostat, take a look at the link below to a DIY tech article from our site on the replacement procedure. Hope this helps you a bit and best of luck!

https://www.pelicanparts.com/techarticles/Porsche-987-Cayman/09-WATER-Replacing_Your_Thermostat/09-WATER-Replacing_Your_Thermostat.htm

Thank you for the reply and link.. I have looked at it before to study the procedure.. very helpful indeed.. Thank you Pelican Parts!