BMW 3 Series Fan Failure Causing Engine to Overheat

Hey there! I faced a similar issue with my 2009 BMW 5 Series last summer. The overheating symptoms were nearly identical to what you're describing. After proper diagnosis, it turned out the fan wasn't engaging because of a faulty connection between the control module and the cooling fan assembly. The mechanic had to replace the wiring harness and check the fan control module. It was quite serious since continuous overheating could've led to engine damage. The repair wasn't just a quick fix, they had to remove several components to access the wiring. What I learned is that with BMWs, electrical issues often masquerade as mechanical problems. My advice would be to find a mechanic who specializes in BMW electrical systems and can properly diagnose with the right diagnostic tools before starting any repairs. Also, make sure they check the coolant level sensor and temperature sensors while they're at it. These can also cause similar symptoms and are often overlooked. Hope this helps with your decision-making.

Hey, thanks for sharing your experience! That's exactly what I'm dealing with right now. Just curious, do you remember roughly how much you ended up paying for the whole repair? And has everything been running smoothly since, or have you noticed any other cooling-related issues popping up? I'm trying to get a sense of what I might be looking at cost-wise and whether this could be part of a bigger problem.

Hey again! Just wanted to update you, I got the fan issue fixed and it was actually a pretty straightforward repair. The mechanic found a damaged cable connection to the cooling fan, which was exactly what was causing the problem. Total bill came to 95€, which honestly wasn't as bad as I was expecting given all the horror stories you hear about BMW repairs! I'm really glad I mentioned my experience because since getting it fixed last month, my car's been running perfectly. No more overheating issues at all. The temperature gauge stays exactly where it should, and the fan kicks in normally when needed. It's such a relief not having to worry about the engine going into emergency mode anymore! From my experience with BMWs, these electrical gremlins can be tricky to diagnose, but once you find the actual problem, the fix isn't always super complicated or expensive. Definitely worth getting it checked out sooner rather than later though, you don't want to risk any engine damage from overheating. Let me know how you get on with yours!

Thanks for the follow-up! I actually took your advice and got my car checked out yesterday. You won't believe it, turned out to be almost identical to your issue. Had to shell out a bit more though, around 150€, since they also replaced some worn-out wiring while they were in there. The mechanic I found was really thorough and took the time to explain everything. What a relief to have this sorted! Just drove it for about an hour today and the temperature stayed perfectly normal. No more emergency mode warnings popping up on my dash. The fan's working like it should now, can actually hear it kick in when needed. Really appreciate you sharing your experience, it gave me the push I needed to get this fixed before it turned into something more serious. It's always nerve-wracking dealing with car issues, but having someone who's been through the same thing definitely helps. Thanks again for all your help!