BMW has a odd note on the install of that pump, it says "Installation note:
If the electrical water pump is used again, it must be turned by one rotation due to the
breakaway torque at the blade wheels." This might have been what made them think the thermostat was not working. Hard to say, I would not have thought to rotate the pump after installing if I had not seen this.

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- 335i E92 2007 [Sapphire Black/Coral Red]
- X5 E70 2013 [Sparkling Bronze/Cinnamon]
"Living the dream" 1981 Delorean #6489