[kewlklown]

okay, where should I start? I have a 2007 335i sedan and the Coolant Level Low warning started one day even though it wasn't low. So I replaced the sensor on the bottom of the expansion tank. No change. Confident I had no leaks I let it ride for a week or two, thinking I'd just replace the tank & sensor and be done with it. Right before I got a new tank, my water pump started draining my battery running for a long time after shutting the car off. In reading various forums I got the idea that my water pump might be on its way out, so I ordered one, as well as an expansion tank w/sensor and cap. After replacing tank and pump and pentafrost I tried to bleed the system using the standard key on-high heat-low fan-accelerator down 10 seconds...no dice, no response...I had read somewhere that the bleed process might not start if it thinks there's no coolant, so I used INPA to run the bleed sequence. Coolant full and bled, still getting coolant level low warning. I might mention I've been chasing a 30FF code for awhile now, I replaced my cold side charge pipe with an aftermarket one from ARM, the one that accepts the OEM DVs(I have a pair from Forge Motorsports with upgraded springs for later when I put back the JB4 and Install DPs, but it's gonna be bone stock till i get to the bottom of all these problems)
Anyway, I've read some things here and there but I'm not sure where I should start. One of the strange things I've read was someone said their coolant light wouldn't go off until they had their brake fluid topped off, which sounds odd yet believable(with these cars, anyway)
so I didn't know where to begin with this post, and I don"t know where to stop, either, evidently...

Any thoughts or help is appreciated especially if you've seen something like this before.
Thanks in advance for any input.