I had to replace a similar pump on client's n52 TWICE. don't buy a knock off but OEM from fcpeuro wasn't terrible. The second replacement was OEM and I bought the thermostat at the same time.

It's such a beast to install I was very happy we found a neighborhood mechanic to do the labor for less than I charged ($250 vs. 300-350)

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)