crud in the cooling system

[miketyler]

Was pulling my old pump off to see this business growing on my timing cover. It cleaned up easy enough but what can I do to eliminate that from coming back when I seal it up?

I was experimenting with a more dilute 50/50 coolant solution. Maybe the water brought that on? I know we have hard water here but I cant figure it has that much to do with this. 

 

[Bullitt-]

Looks to me to be good ole lime deposits...hard water.    Removal would require a cleaner/acid to be run thru the system but unless you use distilled water it will come right back.
I'd say not to worry about it.

[GoodysGotaCuda]

Use Distilled water  I've had nothing but in my block/alum rad since the hot tanking 

[IMNCARN82]

Distilled!!

[Chryco Psycho]

Make sure you do not have voltage in the system as well , I assum the battery ground is attached to the engine with a separate pigtail to the rad wall for the headlights etc