EGR pipe

[JimT]

as to the cause, it should be built to withstand normal operating pressures, so pulling a small hill shouldn't have caused it. If the system was sealed off completely (as I think it would have been) then (as I've been told) excess pressure can potentially build up inside the EGR cooler. Maybe a coolant leak in the EGR cooler, maybe just gaseous expansion due to the heat in and around the system. Either way, I'd suspect marek4792 is right that the pipe was sub-par and just happened to be a weak point.

It was suggested to me while reassembling my engine that, assuming i had BOTH block plates installed, I should leave the clamp on that exact location loose to allow for pressure equalization with the added bonus of being able to see if there's a coolant leak inside my EGR cooler.