Got a few hours to work on the cars today, although most of it went to putting the cooling system back together on the 540i. No pics but the expansion tank was in fact the culprit.
For the M5, I received my first order of parts from Adam. The packaging of everything was exceptional. Most of these parts will go on at a later date since I will be replacing the HVAC assembly behind the dash, the audio harness, and the front carpet. I will likely have the entire interior out of the car so mostly I'm just sourcing everything I need to get it put back together.
Replaced the door sill trim that at the top of the front door (no pics) and replaced the door seal. For whatever reason, the seal that was on the car was in three pieces. This was the same for the passenger side as well.
Here is how the negative terminal was tightened.
I removed the screw and installed the new post tightener from Adam, put the foam in, and installed the cover. However, it seems this magical screw was all that was keeping the battery alive. After doing these fixes the car would just click and won't turn over. I did a little bit of trouble shooting and believe it is a battery issue. When I put the car on the tender, it showed a battery percentage of 0%. It is charging successfully now, but I imagine I will be replacing the battery. I drove the car today with no issues and the problem didn't start until after I finished the work above. Weird.
Very minimal progress today on the M.