No need to jump the gun. Get the test kit to sniff for exhaust in the coolant.

Wife had expansion tank rip in half drive about a mile to a parking lot and then after letting it cool I drive about another mile to where I work on cars. She saw the needle go red and steam from the front when she called me.

Engine got pretty hot but no damage out at least 10,000 miles on before trading up.

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