Debris In Coolant

[ellroy2]

Drained the radiator and the overflow reservoir yesterday. Got just under a gallon out. I used a little hand pump to get as much coolant out of the reservoir as I could. I noticed a little pile of debris/black flakes in the bottom of the reservoir that I could not get out. Should this be something to worry about? Truck has always ran at temp. I have one more gallon of coolant that I will use to repeat the drain and fill after a couple weeks.

 

[radlynx]

i just remove that reservoir and clean it up real good.. there's only around 3 bolts.

 

[Greydog]

It's super easy to get that Res off, 3 bolts, rinse it and reinstall.

 

[BlackWorksInc]

It could be debris, dirt, and/or some sort of growth? I have seen algae like growth in standing coolant before, so I am starting to wonder if this "black" stuff is possibly some biological growth?