Originally Posted by LugNut
OMG!
Finally just did mine this afternoon. What a pain! Actually many pains. Worst in over 30 years of changing plugs.
Didn't remove the coil packs, which would have made it easier, but it did keep the wires in order.
Just under 40,000 miles, and the original plugs were COOKED! Don't believe the FSM's "100,000 miles, or 75K under rough service". If mine were like most, 35,000 miles would be about right. BTW, the originals were generic-looking NGK's, but with MB symbols on them.
Every step was a challenge, all the way to making sure each boot did its final pop-on which wasn't at all easy even after using silicone grease.
Do yourself a big favor and file-smooth the corners and edges of the two aluminum heat shields in the back of the bay before you start this project.
Test-started the XF, but haven't taken it for a drive yet. Wounds are bleeding too much.
I actually did mine last weekend. It was time, just passed about 18k miles on this set with only a few, rare track days.
I actually did mine in two steps. I replaced the wire with Magnacors' a few weeks before, and that was the hardest part.
When I went to change the plugs this past weekend it only two a couple hours, because the wires came out much easier than the OEM wires with the metal expanding shroud.
Also did a battery reset at the same time as I changed the plugs...just cause.