On the M62, the normal progression is;

1) loss of tension at the tensioner
2) chain will loosen and slap the bottom chain guide when you drive over a bump
3) the brittle plastic will shatter and end up in the oil pan
4) this adds a significant amount of apparent length to the chain
5) tensioner can no longer keep the chain tight at all
6) chain will slap anywhere and break more of the brittle plastic
7) tensioner will bottom out and can't even hold chain taught at all
8) the spring pressure of the intake valves on bank one will "snap" the bank one secondary timing chain "advanced" and that after the obvious rattle sound is the typical confirmation of chain guide failure.
9) if left long enough, the chain will get enough slack it will hop off a sprocket, and mass destruction happens.

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)