I continue to have steam coming from my hood for 3 months now while raining.

Hello, Normally I would give you a big description of things that could go wrong, but I'll spare you that. The issue is almost always bad plastic covers underneath the vehicle, allowing rain water to splash onto hot engine components and exhaust. I've seen this issue several times, and since BMW's are so low, they tear up plastic covers left and right. The undercarriage of the vehicle may look fine, but when wind hits it, it may move, and allow water in. Now, I had a 530i with this issue, but my fix was a bad rubber seal for the hood. Water was leaking in, running down the firewall, and landing on the exhaust system. To find the location, on a dry day, spray the entire front of the vehicle for a few minutes at a time, and see when you get smoke. Open the hood, look for the source, and fix what is above it. If you do not get smoke, it is probably the undercarriage covers or inner wheel well covers.