Porsche 991 Overheating: AC Failure & Fan Issues Alarm

Hey there! I had a similar issue with my 2013 Porsche Cayman (I have some experience working on cars, but mainly basic maintenance stuff). The symptoms were exactly like yours, AC blowing hot and engine temp creeping up. The electric fan control unit was indeed the culprit in my case. Took it to my trusted Porsche specialist last summer, and they diagnosed and replaced the control unit. Set me back about 480€, but it fixed the problem completely. Before you go ahead with repairs, could you share: Are you getting any warning lights? Does it happen more when idling? Which engine variant do you have? This could help narrow things down, as different 991 variants can have slightly different cooling setups.

Thanks for sharing your experience! I have the similar symptoms with my 991, currently at 82683 KM since my last service. No warning lights yet, but it's definitely worse when idling, especially in traffic. I actually noticed it first during a long standstill on the highway last week. The temp gauge started creeping up and the AC went from nice and cool to barely lukewarm. Hearing that your fix was just the control unit gives me some hope it's not something more serious. Did your specialist mention any other potential causes they ruled out during diagnosis? I'd rather be prepared if I need to shell out more than 480€.

Hey again! Good to hear back from you. Yeah, my Cayman's symptoms were really similar, especially that highway standstill situation you mentioned. It's like déjà vu, honestly! When I had my car in the shop, my mechanic actually did check a few other things before confirming it was the control unit. They looked at the coolant level (was fine in my case), tested the fan motor itself, and checked the coolant temperature sensor. They even pressure-tested the cooling system just to be thorough. The good news is that all those additional checks were included in the diagnostic fee, which was around 120€ on top of the repair cost I mentioned before. But honestly, based on how similar your symptoms are to what I experienced, especially that idling behavior, I'd put money on it being the control unit. One thing I forgot to mention in my first response: after the fix, I did a long drive through heavy traffic just to test it, and the temperature stayed rock steady. The AC was blowing nice and cold too, even when sitting at lights. Such a relief! But yeah, maybe get it checked soon before the weather gets warmer. Last thing you want is to be stuck in summer traffic with no proper cooling!

Thanks so much for all the detailed info! It's really helpful to hear about the full diagnostic process your mechanic went through. I'm feeling a lot more confident now about what to expect. I'll definitely get it checked out asap, actually just booked an appointment for next Tuesday with my local Porsche specialist. Like you said, better to deal with it now than wait for summer. The way you described the post-repair performance sounds exactly like what I'm hoping for, stable temps and proper AC, even in traffic. The total cost doesn't sound too bad either, especially considering it's a Porsche repair! Really appreciate you taking the time to share your experience. You've helped me avoid a lot of unnecessary worry about what could be wrong. Will update the forum once I get it fixed!