Help Identifying/Removing Radiator Deposits (PHOTO)

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...07.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

"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:

You cant really identify the deposits by photos alone. There are a number
of things
the deposits could contain, such as silicate salts (caused by antifreeze
decomposition),
silicate salts (natural, such as silt from the makeup water), barium
sulfate, calcium sulfate
anhydrite, etc.
You tried to get it out with an acidic treatment, and it didnt work. Take
it to a radiator
shop and let them boil it out with their commercial high pH bath or rod it
out mechanically.

If it is silicate based, you cant get it out yourself (at least most people
dont have the chemicals
to do it).