Ruby (89 syncro Westie) had her cooling system revamped because of an unusual
white deposit on the thermostat and in insulatiing quantities in the microcore
radiator.  

Your radiator is a highly efficient cross flow double stack with really tiny
aluminum channels and fins.  Radiator deposits of any sort severely restrict
heat transfer.  Now the gummygooey stuff that is often found can be treated
by a reputable radiator shop but the white chalky deposit found in Ruby's 
radiator doesn't respond to even the best chemical assailants.  

At 78K the BDD put a generous helping of Alumaseal in to stop the head gasket
seeps.  The opinion of the radiator repair technician was that alumaseal is 
deadly for micro core radiators and starts an irrecoverable process that will
cost you a $425 dollar part at the very least. (radiator list price from BDD).

I am currently negotiating with the BDD to reimburse me for not only those 
expenses but to replace the heater cores.   I'll keep you posted.

IMNSHO Alumaseal is not the answer to the head/gasket design defect.

--
--
         ___  / __   __/   ____/         Al Knoll HP Performance Technology /
        /    /      /     /             Center    Roseville, CA, USA 95747 /
       _____/      /     /             916.785.9453    (Telnet 785-9453)  /
      /           /     /             email:  alf@hpptc38.rose.hp.com    /
   __/         __/   ______/         ___________________________________/