Sludge in water pump
So I recently bought a 2014 Patriot 2.4L (160K miles, automatic, FWD with 4x4) from a guy. He was pretty sure it had a bad head gasket. Started it up and the coolant reservoir started bubbling pretty aggressively, and white smoke started coming from the engine. Scan tool showed cylinder 3 misfire. Seemed consistent with a head gasket issue.
Anyway, I take the valve cover off, and things look pretty clean. Drained the radiator, the coolant was a little murky, but not thick or creamy. Disconnect the radiator and heater core hoses, nothing gross in those. I'm taking the timing chain cover off and realize I can't get it out without removing the water pump. I get all the bolts out and pop the pump off, more relatively clean coolant comes out. Then I pull the pump out and see this.
Does this look like oil in the coolant? That would be understandable if the head gasket is bad. It just surprises me a bit that no other area I've seen looks sludgy like this.
Or could this be some kind of corrosion, or symptom of the wrong kind of coolant?
Is there a good way to flush this out with everything disconnected right now?
Anything else I should be looking at before I take the head off?
Other than the gunk, the pump seemed ok (it was turning fine). With the timing chain cover off, I can see a bit into the oil pan, and nothing looked gross in there.
First time for me doing a project this big, so I'm just looking for any insight or advice.