He should have removed the water pump and inspected the coolant transfer pipe seal facing the water pump or just replaced it all together with collapsible version because that pipe will eventually leak due to seal deterioration from engine heat. Or better still perhaps use the alternative for collapsible pipe "Bimmerfix" as AxGordon had mentioned earlier. Mine was leaking heavily at 110k miles. The rubber gasket of the pipe facing rear of engine was intact but the one facing the water pump had completely deteriorated. I installed the Euro kit pipe and it was actually easy to do.

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'05 E53 X5 4.4i, '97 E39 528, '07 E92 335i, '16 F86 X6M.