BMW 4 Series Cooling Issues: Temperature Trouble Alert

Hi there! I have some experience working on cars, and I actually faced something similar with my 2018 BMW 3 series last year. In my case, it turned out to be just a blown fuse that was causing the temperature sensor to act up. The symptoms were exactly like yours, weird temp readings, check engine light, and slow warm-up times. I took it to my regular workshop, and they diagnosed it pretty quickly. Total repair was 52 Euro for the fuse replacement and diagnostic. But before jumping to conclusions, could you share more details about your car? Like when did these symptoms first appear? Have you noticed any coolant leaks or unusual sounds? This would help narrow down if you're dealing with the same issue or something else. The 4 series is a great car by the way, I'd definitely want to make sure we get to the bottom of this for you!

Hey! I can totally relate to your issue. I've got the same model (2020 BMW 4), currently at 172,715 KM, and had similar problems after my latest service. In my situation, it wasn't actually the cooling grille, turned out to be a faulty thermostat. The symptoms were pretty much identical to what you're describing. The mechanic explained that when the thermostat starts failing, it can cause those inconsistent temperature readings and slow warm-up times you mentioned. They replaced it, and everything went back to normal. Might be worth checking that out before assuming it's the grille. Just my two cents based on my experience with these symptoms!

Hey again! Thanks for sharing your experience with the thermostat issue. You know what's funny? After I posted my initial response about the fuse, I actually discovered more problems with my 3 series. The fuse replacement only fixed things temporarily. A few weeks later, the same symptoms came back, and this time it really was the thermostat, just like what happened with your 4 series! The temperature gauge started acting crazy again, and my engine was taking ages to warm up. Should've known it wasn't just a simple fuse issue. Replaced the thermostat and everything's been running perfectly since then. Cost me a bit more than the fuse repair, around 300 for parts and labor, but totally worth it. These BMWs can be tricky sometimes, but once you figure out what's actually wrong, the fix is usually pretty straightforward. Thanks for mentioning your mileage too, mine's just hit 168,000 KM, so pretty similar to yours. Guess these thermostats tend to act up around this mileage range. Really glad you shared your experience, it's always helpful to hear from someone who's dealt with the same issue!

Thanks so much for that detailed follow-up! It's actually really reassuring to hear that you went through almost the exact same progression of issues. I was starting to worry it might be something more serious, but hearing about your experience with both the fuse and then the thermostat makes me feel much better about the situation. I'll definitely get it checked out this week. I've got a trustworthy mechanic who specializes in BMWs, so I'll mention both the fuse and thermostat possibilities to him. The 300 price tag you mentioned sounds way better than what I was imagining, I was worried it might be something in the thousands! Really appreciate you taking the time to share your experience, especially since our cars have such similar mileage. It's super helpful to know what to expect. Will update you once I get it sorted out! Thanks again for all the help!