HELP with E70 N55 engine seize diagnosis

[tdpyron]

I've seen a couple of mentions about an N55 B30 engine seize while driving. Same happened to me. I had driven 160 miles and stopped briefly (5 min). Restarted the car, did an unplanned full-throttle acceleration to speed to avoid an oncoming car while I merged. At speed the car tripped to neutral and 0 RPM. Mechanic later told me crank was seized (trans put in neutral, no oil in coolant or coolant in oil, pulled one plug and horoscopes for hydrolock, can't manually turn the shaft). Not pulling the lower oil pan ($$) - he thinks main bearing spun.

History: Two days prior I had just had the valve cover and gasket replaced and water control valve with new. Drove the car - immediately got a low battery warning and replaced the battery. They cleared some faults with the battery change. About a month prior to that, they replaced the oil filter cover gasket and oil cooler gaskets (leaking badly). Likely unrelated - have a short blowing 132 fuse in the back (likely comfort access as I've had ongoing problems with the handles).

Seen a few mentions of engines seizing after replacing oil filter cover gaskets... otherwise this problem has stumped most.

125k miles

[Lviv777]

I did the oil filter gaskets a few thousand ago, and my engine is at the exact same mileage, surprised this happened. https://www.e90post.com/forums/showt...1565205&page=2 check out this thread. Seems like repairs recently could have caused that.

[tdpyron]

Yeah I read that thread - way too similar. That's why I thought I'd post again. I'm not sure if there is causality there or not. But an engine spinning a main bearing (current thinking) while driving under stress (I was at full throttle) just seems very odd. My mechanic is a good guy - I just don't know if I should be counting this as "bad luck" or something related to the just-done repairs.... it's just too coincidental.

Thanks again.