brown colored water

[mtnwingrider]

Ok so the water pump change out went well. All back together and seems to work fine. No leaks at all. When I drained the system getting ready to do the change out the antifreeze had turned brown. Hmmm I thought. NO symptoms of head gasket leaks at all. None. So when I got it back together I started flushing it with distilled water. First flush had a bit more brown but not as bad. After four flushes with distilled water I was still getting some discolored water and it had a very fine black sediment. Not much and it wasn't gritty at all. Well I thought I might as well do a serious flush. I got some prestone clean and flush and followed directions. It's to cold to ride here without antifreeze in it so I opted for the 10 minute flush and I pushed that to a full 30 minutes. More brown. Two more flushes with distilled water and still discolored. Odd thing is when I pull the plug in front of the water pump, the first half of the water seems absolutely clear then the last bit seems to discolor the rest. Just a very small amount of that sediment. Again NOT gritty, you can't even feel it between your fingers. Why after seven flushes with distilled water and one with prestone is the water still colored (I run the bike to normal operating temp and let the fan kick on and off a few times before stopping and draining). What is that microfine black sediment? Any help would be appreciated.

[Aussie81Interstate]

why don't you flush your radiator - it could well be that just draining the radiaotr is not clearing all the sediment.

take the radiator off then remove your thermostat and flush with a hose or something similar. Reverse flush the radiator will probably yield some results..

[mtnwingrider]

When the radiator was off during the water pump replacement it was flushed both ways with boiling water. The first flush produced some brown water but by the end flushing in either direction produced nothing but clear water

[redial]

My uncle, on his old vehicles, would use clothes washing powder when the radiator had some rust buildup. I dont know whether it works, especially on later designs, but it could be something more to consider in the flushing. This could be the effect of someone putting straight water in to overcome a problem, and then didnt bother to flush it out later. Just thinking out loud, but be aware it might be a bit rough!

[HawkeyeGL1200]

Someone probably ran with straight water in the system for a period of time and corrosion formed inside the engine. Flushing with a mild acid, like vinegar, might speed up the crud removal. You can also refill the system and run it with anti-freeze for a month or two and then drain and flush again. It's annoying to find these things after a maintenance activity, but it happens to us all.