BMW X1 Temperature Issues: Erratic Gauge & Slow Warm-Up

Hey there! I have some experience working on cars and went through something similar with my 2012 BMW X3. The symptoms you're describing sound really familiar. I had erratic temp readings and warming issues too. Turned out it was just a blown fuse controlling the temp sensor circuit. My trusted mechanic found it during inspection, quick fix, just needed a new fuse. Cost me 52 Euro and about an hour of labor. But before jumping to conclusions, could you share: Are you getting any specific error codes with that check engine light? Does the temp gauge swing out of nowhere or just read incorrectly? Notice any coolant leaks? These details would help nail down if it's the same issue I had or something else. BMW temp systems can be tricky, and there could be other causes worth checking.

Thanks for jumping in! I just had my service done last month at 64,723 KM, and everything was fine until now. The temp gauge actually swings out of nowhere, sometimes it'll show normal operating temp, then suddenly drop to cold, then shoot up again. No visible coolant leaks that I can spot, but I'll check for error codes tomorrow. A blown fuse would be a much better scenario than what I was imagining. Was your temp gauge also this erratic before you got it fixed?

Oh hey again! Yeah, my temp gauge was doing exactly the same dance as yours, that unusual swing from normal to cold and back up was driving me nuts! And since you mentioned your recent service, that's actually pretty similar timing to when mine started acting up, I was about a month post-service too. When my gauge was going crazy like that, I initially thought it was something major, but the fuse thing was such a relief. And yes, my readings were just as erratic as what you're describing. It would look fine during idle, then suddenly drop while driving, which made absolutely no sense. The unusual swings stopped completely after the fuse replacement. Since you're going to check the codes tomorrow, I'd suggest looking specifically for P0128, that's the code I got. If you get the same code, it's probably the same issue. The fact that you've got no visible coolant leaks is also a good sign, that was the case with mine too. Just one quick tip though, might be worth checking your fuse box yourself before heading to the shop. The temp sensor fuse is pretty easy to spot in the manual. Could save you some time and money if that's all it is! Let me know what those codes show up. Really curious if you're dealing with the same gremlin I had!

Thanks so much for all the detailed info! You've definitely given me some hope that this might be simpler than I feared. Just checked my manual and found the fuse box diagram, I'll take a look at that sensor fuse first thing tomorrow morning. Really appreciate you mentioning that P0128 code too, will keep an eye out for that when I scan it. The similar timing after service is quite interesting, makes me wonder if something got knocked loose during the maintenance. Will update you once I've checked both the fuse and the codes. Thanks again for sharing your experience, it's super helpful to know someone else dealt with the exact same symptoms and got it sorted without major repairs!