I second that. I did my 03 4.6iS at 110,000 and they were very brittle. Easily broke pieces off when removing. It’s not a matter of if they are going to fail only when, kind of like an aneurism.
Since the 4.6 motors are so rare fixing it after the fact it’s typically not done do to the scarcity of blocks. Look up Terminator and his efforts to fix his 4.6. He finally gave it up.

__________________
A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools. -Douglas Adams

2003 X5 4.6is Estoril Blue
2005 Infiniti G35X
1972 Datsun 240Z
1991 Isuzu Impulse XS Sold
1972 Fiat 850 Spyder Donated
1972 Datsun 240Z Sold
1972 Datsun 510 Sold