Two separate instances of this problem about 24 months apart. Now showing same symptoms again. Wish Buick would address the fact that there's a design flaw with this engine.
Why are the rocker arms working themselves out of the cylinder head? on 2003 Buick Century
TRY LOCK TIGHTING THE BOLTS IN THIS TIME
I should have mentioned that I am NOT a mechanic. My local shop is great and fixed the first two cylinders that did this. They used I believe what they called a helicoil? I suppose I'll just end up doing this again when the next cylinder bolt lets loose.