Originally Posted by osteopathXI
I would have paid for the water pump $(475 at Tischer) and had them replace it when they replaced your t stat. Then you wouldn't have had to pay any labor when the wp finally does go since its the same labor to replace t stat as wp.
This is completely wrong. Replacing the waterpump would have added additional labor cost to the repair. The t-stat is bolted to the waterpump. The water pump does not need to be removed from the engine to remove the t-stat. The t-stat comes off first during a WP replacement so there is no extra labor to replace the T-stat when doing the waterpump, but there is extra labor cost to replace the waterpump when in there just to replace the t-stat.
They most likely replaced the coolant as part of the repair. The t-stat is at the bottom of the cooling system, so the cooling system needs to be completely drained to replace the t-stat. If the coolant was fresh, the dealer could have saved it and reused it, but based on the milage, they most likely used new coolant. Check the parts bill of material on the repair order to see for sure. If they replaced the coolant there will be a P/N for 1 gallon of BMW antifreeze.
Additionally, one dealer would not buy a waterpump from another on-line BMW parts retailer such as Tischer; they would have charged the OP the full BMW MSRP for the pump and added it to the bill. Also they would not warranty the work if they used customer-supplied parts (even if it was a OE BMW part in an unopened BMW parts box).