What is the potential cost of a failure? Looks like you've got a OM603 with an alloy head, a no-name cheap plastic pump with a claimed 100C upper temp limit sounds like a quick way to a $2000 cylinder head overheating event, all to save not even a hundred dollars? Bosch 001-835-13-64, listed on Peach Parts for $90 and Amazon for $55 and up

Coolant temps can easily get over 100C in traffic, climbing a grade etc.