[whynotthinkwhynot]

The dealer said you had a coolant leak at the pump, right? Have you had to add coolant at all?

If you do decide to flush the coolant, let us know and we can guide you through how to do it at home with a hose. That's a lot cheaper than most places that ask you for $1-200 for a coolant flush. Who knows if they actually flush.

IMO, unless you're losing coolant, there's no need to do anything. A little trash in the reservoir is no big deal. You have an all aluminum engine, so that's not rust. If it's pieces of your water pump- you'll soon have other symptoms. If you are loosing coolant, then you have a much bigger job ahead of you if that coolant is coming from the water pump as the dealer suggested.