Sediment in Coolant?

[colourclassic]

Sediment in Coolant?

Has anyone seen this before? I've just bought a 2006 Mitsubishi Triton and it has a brown flaky sediment in the cooling system.

The stuff isn't gooey like oil mixed with water, and instead is a flaky particulate which when rubbed disintegrates into nothing. 

It was mostly in the coolant reservoir, accumulated at the bottom of the bottle but also on the walls at the water level. I'd say there was about a half a teaspoon of the stuff in there.

I pulled the upper radiator hose off and it seems to be lining the walls of the hose, however here i had to use my fingernail to scrape it off as opposed to it just rubbing away easily.

 

I've seen oil mixed with water in head gasket cases but it seems to form a more solid, milky gooey mass. This stuff is more like tiny specs of matter which when rubbed basically just disintegrate like I mentioned above. The car doesn't appear to lose any oil or coolant. I've cleaned it all up and will see if it reappears, just not sure what it is? Possibly hose rot or contaminated coolant?

 

Pics attached. 

 

[vxsr33]

My guess is mineral deposits, probably from using undistilled water?

I've had similar sediment in my vx commodore, i just flushed the system and used distilled water with the coolant and its all good now.

[Victory]

I would also suggest that the residue is from using tap water instead of distilled water in the coolant.

A couple of flushes of the system should go a long way towards removing those mineral deposits from the system.