BMW 3 Series Temp Gauge Mystery: Cold Engine Blues

Had a similar situation with my 2003 BMW 5 Series diesel (E39). Started with slow warm-up times and irregular temp readings. My mechanic found the fuse controlling the cooling fan was blown, but that was just part of the problem. The main issue turned out to be a faulty thermostat and a partially clogged radiator. Got it fixed last month, needed a thermostat replacement, radiator flush, and new coolant. Wasn't a severe problem yet, but could have led to overheating if left unchecked. Your symptoms sound familiar, but I'd check the basics first: coolant level, fuses, and thermostat. A blown fuse is the easiest fix, while thermostat issues need proper attention. Worth getting it checked soon before it develops into something bigger. Just a heads up, the check engine light could be related or a separate issue. Best to get it scanned first to rule out other problems.

Thanks for sharing your experience, really helpful info! I've got similar symptoms in my car, and I'm thinking about getting it fixed soon. Would love to know how much you ended up paying for the whole repair job? Also, has everything been running smoothly since the fix, or have you noticed any other issues popping up? Trying to figure out if I should expect any follow-up problems with mine.

Hey there! Just wanted to follow up on your questions. After my last post, I actually took the car back to the mechanic and they found the cooling grille was indeed restricted, that's been fixed now and it's made a huge difference! The total bill wasn't too bad, paid 52€ for the fuse replacement, which was a pretty straightforward fix. The whole cooling system's been working like a charm since then. The temperature gauge is now behaving normally, and warm-up times are back to what they should be. No more check engine light either, which is a relief! It's been about three months since the repairs, and I haven't had any other issues pop up. The car's running better than before, so I'd definitely recommend getting yours checked out soon. These BMWs are pretty solid once you sort out the cooling system, just need to catch these things early before they turn into bigger problems. Let me know how you get on with yours. Always happy to share more details about my experience if you need them!

Just wanted to update everyone who helped. Finally got my car sorted at a new mechanic I found. Turns out you were spot on, had multiple issues with the cooling system. The thermostat was shot, and they found some gunk blocking the radiator. Got everything fixed up last week. Bill came to about double what you paid, but they did a thorough job. Had to replace the thermostat, flush the whole system, and put in fresh coolant. They also cleaned out the cooling grille while they were at it. Car's running like new now! The temperature gauge is steady, warm-up time is back to normal, and that annoying check engine light is finally off. Really glad I didn't wait any longer to get it checked out. Thanks again for all the advice. Saved me from what could've been a much bigger headache if I'd kept putting it off!