While the shop has the head, have them check the condition of the valve train (valve guides and seals). It is very easy (and incrementally expensive) to go ahead and have those refreshed while the head is off.

Once you get your car back together, use anti-seize paste on the GP threads, and plan to change them proactively every 50 k miles, and you should not have a problem in the future.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech