"Martin" wrote in message
oups.com...
Looking at a vehicle with a cooling problem, I found the radiator to
contain these rough deposits which resemble the lime/calcium
deposits
found in showerheads:


http://pg.photos.yahoo.com/ph/funkyc...40cf&.dnm=ca07.
jpg&.src=ph

The true color is actually a little more white and a little less
brown
than it appears here. The texture resembles coral or concrete, with
a
dry/granular nature.

There is no substantial rust in the system, only this stuff. I also
removed the lower hose, and found no crud. Also, the wire "spring"
inside the radiator hose is not rusted. The problem appears to be
confined to the upper part of the tubes.

I tried the two-part oxalic acid / neutralizer distributed by
Prestone,
with no effect, so it's not limestone

Can anyone identify these deposits, and recommend a treatment? Is
there any in-situ treatment known to remove this? If not, what
would a
radiator shop do I remove the radiator and take it in?

thanks,

Martin

Looks like silicates from the ethylene glycol...