DIY for electric water pump replacement?

[GriffX5]

Wish I had seen this thread earlier.
I have a 2012 X5 with 110,000 miles. I've had the ridiculously loud fan thing going for a while, didn't think much of it (other than that my car seems to be trying to speak whale), most Mercedes seem to have loud ACs so I figured it was normal for zee Germans. Then one day I get the red thermostat symbol in the cluster and the car went limp. Got it to the dealer and was told $1900 out of pocket for a water pump and thermostat. I laughed and said 'do you really think i would have come to the dealership if I didn't have a warranty?' lol. So he calls back later to tell me I only have to pay the deductible ($400) the warranty will cover the remaining $1100. Can't wait to find out why the price dropped once a warranty was involved.