Electric Fan Failure Causing Critical Engine Overheating

As someone with some hands-on experience, I had a very similar issue with my 2006 Golf, basically the same cooling system setup as your Bora. The temperature control problems you describe match exactly what I experienced. After diagnosing, it turned out the electric fan wasn't activating properly due to a damaged wiring connector at the radiator fan motor. The cooling system itself was fine, but the faulty connection meant the electric motor wasn't getting proper power to run the fan when needed. Got it fixed at my regular workshop for 95€, which covered the electrical repair and testing. Since then, the radiator fan kicks in consistently and engine temperature stays normal, even in stop-and-go traffic. Before jumping to conclusions though, could you share: Does the fan ever work at all? Are there any warning lights on the dash? Have you noticed any coolant temperature sensor errors? Does it happen more during specific driving conditions? This information would help determine if your issue is identical to what I experienced or if there might be other factors affecting your cooling system.

Last serviced at 138923km. Thanks for the input. Quick update: the fan does work occasionally but seems unusual. No warning lights. Most noticeable when stopped at traffic lights or driving slowly. I checked the wiring connection you mentioned, there is visible corrosion on the fan motor connector. The cooling system otherwise appears normal. Timing matches what you described, temperature spikes mainly during low speed or idle. The repair cost sounds reasonable if it solves the vehicle overheating problem. Temperature control issues are really starting to worry me, especially with summer approaching. Going to have it checked at the shop this week and will update once the electric motor or wiring gets inspected. Appreciate the detailed response and repair cost info. Will report back with what they find.

Thanks for the update on your Bora. The corrosion you found on the fan motor connector definitely matches what I discovered on my Golf. That visible damage is often a clear indicator of why the electric fan behaves erratically. In my case, the mechanic also noticed the radiator fan would spin freely by hand when the engine was cold, suggesting the fan motor itself was still good. The vehicle overheating was purely down to the electrical connection issues. One thing to watch for during repair, make sure they thoroughly clean and protect the new connection. My workshop applied dielectric grease to prevent future corrosion, which has kept the fan working reliably for the past year. Since your symptoms align so closely with what I experienced, I expect you will be looking at a similar 95€ repair cost. The temperature control should return to normal once the electrical connection is restored, particularly during those critical idle periods when the electric fan is most needed. Looking forward to hearing the workshop diagnosis. The correlation between your description and my previous repair experience suggests you are on the right track focusing on the fan motor wiring.

My corroded fan motor connector got fixed today, mechanic found exactly what was suggested. Cost was 110€ for cleaning connections, replacing the damaged connector, and applying protective coating. They also tested the electric motor and fan clutch which were both working fine. After a 30-minute test drive through slow traffic, the temperature control is back to normal. The cooling system is maintaining proper temps even when idling. Electric fan now kicks in consistently when needed. Really glad it was just the wiring causing the vehicle overheating and not a more serious issue. Will keep monitoring the temperature gauge for a while but it seems the repair has solved the problem. Much cheaper fix than I initially feared when seeing those high temperature readings. For anyone searching later with similar symptoms, definitely worth checking those fan motor connections first before assuming worst case scenarios. Thanks again for pointing me in the right direction with the electrical diagnosis. Would have probably spent more time and money troubleshooting without that specific guidance.