Phaeton Overheating: Electric Fan Motor Failure Alert

Having worked on my 2011 VW Passat diesel, I can share some relevant experience with similar engine cooling issues. After noticing temperature control problems that match what you describe, I discovered the radiator fan and its electrical connections were the culprits. The fan issues started exactly like yours, inconsistent operation and rising engine temperatures during all driving conditions. My mechanic first checked the fan clutch and the entire cooling system before identifying faulty wiring at the fan connector. The insulation had worn away, causing intermittent electrical contact. The repair involved replacing the damaged wiring harness and connector assembly, costing 95€ including labor. Since then, the engine cooling system has worked flawlessly with proper fan engagement. Before suggesting specific solutions, could you share: Has the fan clutch been inspected? Are there any error codes stored in the system? When was the last cooling system maintenance performed? Does the overheating occur more in specific conditions? These details would help determine if your Phaeton is experiencing the same electrical connection issues I encountered. While the symptoms sound similar, properly diagnosing temperature control problems requires checking multiple components in the cooling system.

Thanks for the detailed response. Last service was done 3 months ago but the cooling system wasnt specifically checked. The fan issue started about 2 weeks ago and gets worse during stop-and-go traffic. The fan motor seems to run sporadically, sometimes it engages normally, other times it wont activate even when the engine temperature is high. No error codes are showing. The fan clutch looks intact based on visual inspection but hasnt been professionally checked yet. Good point about the wiring, will have the mechanic inspect the connections since electrical issues seem common in the cooling system. The overheating happens most severely during idle and slow city driving when theres less airflow through the radiator. On the highway it maintains better temperature control but still runs warmer than it should when the fan isnt engaging properly.

Sounds exactly like what I experienced with my Passat. The inconsistent fan operation, especially during idle and city driving, strongly points to an electrical issue in the cooling system rather than a mechanical fan clutch problem. When my vehicle overheating issues started, the symptoms would come and go out of nowhere, just like yours. The intermittent nature of the electric fan operation is a classic sign of wiring problems. The connection degradation tends to worsen with heat and vibration, which explains why the symptoms got worse over time. Since no error codes are present and the issue is most noticeable in stop-and-go conditions, have the mechanic focus on: 1. Fan motor connector pins for corrosion 2. Wiring harness condition near hot components 3. Ground connection integrity 4. Fan relay function In my case, the repairs lasted about 2 hours and the parts were relatively inexpensive. The temperature control has been perfect since fixing the wiring, with the electric fan engaging exactly when needed. Worth checking these electrical components before replacing the entire fan assembly. The fact that highway driving shows better temperature control further supports an electrical rather than mechanical issue in the engine cooling system.

Given your feedback about my electrical issues, I decided to have my Phaeton checked by the workshop. You were right, they found corroded pins in the fan motor connector and some damaged wiring near the radiator. The harness had rubbed against a bracket, wearing through the insulation. The total repair cost was 180€, which included replacing the wiring harness section and installing a new connector. The electric fan now engages consistently and the engine cooling system is working perfectly. No more overheating issues during city driving or at highway speeds. The temperature control is much better, staying within normal range even in heavy traffic. Really glad I had them check the electrical connections before replacing the entire fan assembly. The vehicle overheating problem was resolved without any major component replacements. Thanks for steering me in the right direction with the wiring inspection suggestion. Would have spent much more time and money troubleshooting without that specific advice about the electrical system.