water pump

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So, I'm driving around enjoying my boxster when I notice some steam (right side of car). I'm thinking hose, maybe water pump. Sure enough I get home and realize it's the water pump. Fairly easy removal. Bearing is destroyed and blades are chewed off. Now comes the hard part. I removed the thermostat housing and found some broken parts but not much of the blades. I put a hose where the thermostat sits, undid the large hose from the engine and of course the water came out but no parts came out. Is there an easy process to back flow the coolant? I really don't want to take everything apart if I don't have to. I've installed the new water pump and filled up with water (to look for possible leaks) and bled the system (pretty sure I did that right). But now I'm having second thoughts about getting ALL the broken blades out. I don't drive the car all that much. What are my odds that this WILL lead to major damage. Thanks for your reply