Boxster's Mystery Overheat: Thermostat vs Other Culprits

Hey there! I had a somewhat similar issue with my 2008 Cayman (and previously owned a 911). I have some experience working on cars, mainly basic maintenance. Had my car overheat last summer, turned out it wasn't the thermostat but actually damaged wiring harness that was messing with the cooling system sensors. My trusted mechanic found some chewed up wires (probably rodent damage). Total repair was around 110 Euro and solved the overheating and CEL issues completely. What specific symptoms are you seeing? Is the temperature gauge climbing gradually or spiking suddenly? Any coolant leaks visible? These details would help figure out if you're dealing with the same issue I had.

Hey, thanks for sharing your experience! My mileage is at 86224 KM and I'm having slightly different symptoms. The temperature tends to spike pretty quickly, especially in city traffic. Had it serviced just last month but this started happening recently. Haven't noticed any visible coolant leaks under the car, but I'll definitely have that wiring harness checked too, didn't even think about that possibility! Did you notice any specific warning signs before your wiring issue got serious?

Hey again! Yeah, with my Cayman, I actually did notice some warning signs before the major problems started. At first, I had these unusual temperature fluctuations, especially when idling at traffic lights, sounds pretty similar to what you're experiencing. But here's something interesting: before discovering the wiring issue, I also suspected the thermostat like you did. In my case, before the mechanic found the chewed wires, I noticed the temp gauge would sometimes act a bit erratic, jumping from normal to hot pretty quickly, then back down again. That's actually different from a typical thermostat failure, which usually shows a more consistent pattern. Since your mileage is pretty close to what mine was when I had the issue (I was around 89000 KM), it might be worth checking both. One quick tip from my experience, if you're planning to get it checked, try to notice if there's any pattern to when the temperature spikes happen. Like, does it happen more when you first start the car or after it's been running for a while? This helped my mechanic narrow down the problem faster. The wiring issue in my case was actually pretty subtle until it wasn't, if you know what I mean! But yeah, given your symptoms, I'd definitely have both the thermostat and wiring checked out. Better safe than sorry with these cars, right?

Thanks so much for all the detailed info! That's really helpful about the temperature patterns, now that you mention it, I've noticed it tends to spike more after the car's been running for about 15-20 minutes, especially in stop-and-go traffic. I'll definitely keep track of when exactly it happens before taking it to the shop. You've given me a much better idea of what to look out for and what to tell the mechanic. Really appreciate you sharing your experience, it's definitely less stressful knowing someone else has dealt with similar issues. I'll update once I get it checked out. Thanks again for taking the time to help!