No sooner I put the tools away from replacing the exhaust downpipe bolts going to get them out again, alternator failing, not charging made it home with 11 volts. Alternator was a used one I put in whilst my original was rebuilt last year so the rebuilt unit is in the garage wondering if I should just change the diode pack or change the units over less work just changing the diode pack. Think I will change the units then have the duff one rebuilt as a spare. Use a local Alternator and Starter rebuilder who is very resonable and uses oem diode packs when servicing BMW Alternators.