Drained coolant today, looks like blood Muha!

[gregorio]

Installed the new t-stat and looking at this stuff like wow! I can't remember when I changed it last. Might be nothing to worry about just looks bad to me.

The picture is after I pulled the rear freeze plug out of the ds head.

 

[gregorio]

Jesus... rough crowd

 

[Jimmysidecarr]

If you can't remember changing it then it would br best to flush it and replace with a new mixture.
Antifreeze/water mixtures can become corrosive in as few as 4 or 5 years.