Please don't shoot yourself.

Any estimates or declarations of the cause at this point have worse odds than if you shoot an arrow in the air expecting it to pierce your skull when it comes down.

See if you can find where the coolant came from. It could be as simple as a hose that blew coolant all over the engine. The cooling system is pressurized and coolant is being circulated by the water pump. When anything in the system ruptures the coolant is quickly projectile vomited.

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X5 4.6 2002 Black Sap, Black interior. 2013 X5M Melbourne Red, Bamboo interior
Dallas