Black ashy debris in coolant reservoir

[CTUBS8732]

Radiator blew and limped it home. Overheated a little but not all the way to the max. Replaced with a 4 row aluminum Radiator and now I noticed at highway speeds my temp stays at 154° and at idle it warmed up to about 226° then fan kicked on and temp went down to about 195° and slowly rose back up, i have black specs floating around. I smeared some and it looks to be ashy not so much as greasy or oily. What could the stuff be? Also I was having trouble burping the system. I did not flush it as I should have done it. I've done some research and all I can find is blown head gasket but it's not oil or at least I dont think it is. Its like little black specs that look like black ashes floating around.

 

[Fless]

If you suspect a blown head gasket try using one of the testers for exhaust gases in the coolant:

How To Test Coolant for Exhaust Gases - A Complete Guide

Test coolant for exhaust gases is important for maintaining your vehicle's engine health. Exhaust gases in your coolant may indicate engine damage.

bryansgarage.com

 

[CTUBS8732]

If you suspect a blown head gasket try using one of the testers for exhaust gases in the coolant:

How To Test Coolant for Exhaust Gases - A Complete Guide

Test coolant for exhaust gases is important for maintaining your vehicle's engine health. Exhaust gases in your coolant may indicate engine damage.

bryansgarage.com

Got some of the debris on a paper towel seems like it's small specs from the heater hose. It smears but it's not oily or greasy.