I took one out and put a new copper washer on to seal a leak on a 2010 one and it was OK. Mine came out easily but some report major problems.
There were some comments in one of posts in last 6 months or so about doing it. It may be on members motors bit.
I think soft exhaust paste (that does not set) was advice that was given afterwards.
May have to clean up the sealing face on the block with special tools if not reseating.
Good luck