Cayenne Diesel Overheating & Coolant Loss: PTC Issue?

Hey there, I had the exact same issue with my 2012 Porsche Panamera Diesel last winter. The symptoms were identical, coolant disappearing, engine temp rising, and that annoying warning light. Turned out the PTC heater was completely shot and was leaking coolant into the system. Took it to my trusted mechanic who specializes in German cars. They had to remove the entire auxiliary heater unit to access the problem. The PTC heating element had corroded badly and needed a complete replacement. It wasn't a quick fix, took them about 6 hours to complete the job. This isn't something you want to ignore, the auxiliary heater failure can lead to bigger engine problems if left unchecked. Mine was caught just in time before it could cause any serious damage to the engine. Can't recommend specific mechanics in your area, but make sure whoever you choose has experience with Porsche diesel systems. These auxiliary heaters are pretty specific to VAG diesel engines and need someone who knows what they're doing. Hope this helps.

Thanks that's really helpful! I'm glad I'm not the only one who's dealt with this. Sounds like I'm looking at the same issue with my Cayenne. Just curious, do you remember roughly how much the repair set you back? And has everything been running smoothly since, or have you noticed any other quirks pop up? Thanks!

Hey again! Just wanted to follow up, yeah, after getting it fixed at my mechanic, everything's been running like clockwork! The repair cost me 350€ to fix the faulty electric auxiliary heater, and honestly, it was money well spent. The PTC heater is now working perfectly, and I haven't had a single warning light or coolant issue since. It's such a relief not having to constantly check the coolant levels anymore! My Panamera's been performing brilliantly through all weather conditions, and the heating system is working exactly as it should. I can finally enjoy those chilly morning drives without worrying about the engine temp going haywire. Just keep in mind that these German cars need specialized attention, but once you get the right fix, they're absolutely solid. If you end up getting it repaired, make sure they do a thorough check of the entire heating system while they're at it. Let me know how it goes with your Cayenne!

What a relief! I finally got my Cayenne sorted. Took your advice and found a specialist mechanic who really knows his Porsches. You were spot on, it was the PTC heater causing all the trouble. Cost me a bit more, around 450€, but they did a complete system check while they were at it. Funny story actually, when I got to the shop, the mechanic took one look at the symptoms and knew exactly what was wrong. Said he'd seen it plenty of times before. The repair took most of the day, but what a difference! No more warning lights, steady coolant levels, and the engine's running at perfect temp now. Thanks again for pointing me in the right direction. It's such a weight off my shoulders not having to worry about topping up coolant every few days. The Cayenne's back to being the reliable beast it should be. Really appreciate all your help with this! Take care!

Hello, I have the same problem in my vehicle, aca if I want to show your master, could you share your information with me,

(Translated from Turkish)

Start by checking for any visible coolant leaks around the engine bay, especially near the auxiliary heater unit. If you notice any leaks or if the coolant level continues to drop, it's important to have a professional inspect it as soon as possible to prevent further damage. Let me know how it goes or if you have any other questions!