My determination on e53 is the factory cracked the paint on the pipes just about under the driver's left foot on LHD car which allows corrosion take root.

When my pipe sprung a leak, the entire pipe was "made of rust" there wasn't 20% left of the original paint and that's with 180.000 or so miles.

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