2003 X5 4.6is timing chain tensioner. I replaced it.
Installed the latest and greatest part.

I knew this was coming, but unnerving all the same.
The initial 1 to 2 seconds sound awful.

It took a few seconds to build up pressure. I'm sure it's totally normal
but sounded like the last gasp of death for the rare 4.6.

It's not a difficult procedure, and I feel they are a 50K replacement item.
Since the timing chain guides are a known problem, I feel a good tensioner
(Might) stave off the damage.

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2003 4.6is X5
2003 525it
2003 E53 X5 Standard shift