[1 Bimmer]

60K miles. Changed spark plugs. No real challenge, just took time to remove the cabin air filter assembly below the windshield. Need to do this to expose the rear 2 cylinders. Videos on line showed how to use a screwdriver to pry up on the coil and they popped out. Did not have to remove the strut brace/bar. Also shows how to remove the wire looms and cabin air filter assembly. Had no codes, but had a misfire/hesitation when trying to accelerate at about 2k RPM in 6th gear at about 70mph. Old plugs had noticeable wear on the center electrode. Gap was .050-.055 while new plugs were .040. Hesitation seems to be gone now. Plugs are recommended at 60k miles, but seeing the wear, and if it is linear at about .002 every 10k miles, I think they should be replaced every 40k miles. I'll try that interval next time or when/if the hesitation comes back. NGK plugs, with bright plating on the threads that is supposed to have lubricity so they recommend no anti-seize. Finger tight, then 90 degrees, easy. From FCP Euro, NGK 95712 at $65 for 6.

Had a teaspoon of oil in the last cylinder next to the firewall. Valve cover gasket? Mopped it up before putting in the new plug. Front valve cover bolts did not move with reasonable effort, back ones did move a few degrees tighter. Bolt heads needed a torx socket. Glad I bought a torx socket set, a cheapie set at Autozone for $20. Looks like many other bolts in the engine bay have positive torx heads that require a socket.

(N52 in a 2013 128i)