Did you ever resolve the battery issue?
What's your average fuel economy when you drive like a grandma in the M5? (If that circumstance ever occurs. :lol: )
Battery was DEAD. So I actually managed to jump it using TWO of those LiIon jump starters--one in the trunk on the battery, and the other on the terminals under the hood. It BARELY turned over, but apparently 1600 CCA was enough when 1000 CCA wasn't.
But I took it to Autozone, where I still had the reciept, they had to run their tests. I think their meter said it was at something like 45 CCA. So they ended up giving me another AND resetting my battery warranty due to a stroke of luck. Now I keep the car on a float charger pretty much all the time and haven't had any issues.
I'm almost never driving my car anymore--either take the wife's or bike. But around town it's really not great, even when driving like a grandma, just due to allllll the stop lights and stop signs. On the highway, I think i was mid 20s on the way to Texas at 75 mph. Not bad!
My next project is the thermostat. It definitely needs to be replaced (stuck open), which has only helped me not want to drive it during the winter. Getting to the thermostats is kind of a PITA, made easier by removing the giant plenum under the hood. Removing that is also a PITA with a million dissimilar screws--i've yet to have it off myself, so we'll see! But once you have the plenum off I think I'll probably end up going crazy with replacing all the other 20 year old tubes that are undoubtedly deteriorated down there.
I also think i'll do valve cover gaskets, as I think thats at least one source of my slowww oil leak. When I looked through the old service records they'd been replaced like 5 times, and when I did spark plugs a few years back (man I should do those again too
) there was lots of oil in some of the wells.
Picture of the intake plenum: