Doesnt appear to be mixing with oil but the coolant is black!
1998 blazer...

 

Whatever is causing it, get it flushed out now!

 

Only thing that comes to mind is a blown head gasket, though usually you lose coolant. One other thing might be a worn out, ready to replace water pump.

Scratching my head to think of other possible causes.

 

Did you just get the vehicle?

Someone might have put alot of stop leak in the cooling system to cover up a problem

 

What comes to my mind is did someone add green antifreeze to a Dexcool system? When you mix the two you get a nasty brown/black color.
ALL 1998 GM products used Dexcool antifreeze.

 

oil in the coolant?

 

This happened to me once a few months back, the black color was rather sooty, I flushed the coolant out and replaced with new. No problems since...I read a thread on this site, if I remember correctly, and someone suggested it may be the rubber wearing from new coolant hoses, I dismissed it as probably the culprit. I replaced both weeks before I seen the black stuff in the coolant. Hope that helps.

 

Checked out the ride today i concluded it is either stop leak or new hoses...

No oil in coolant or vice versa coolant level stays the same... No smoke what so ever so either tge stop leak fixes the headgasket problem i dont think i have a major problem....

 

I found nothing black water in mine and I believe it came from the hoses....inside was flaking apart and touching turned finger black. Flushed well and new hoses and all is well