On my soapbox again!

You can spend a lot of money on long antiquated coolant chemistry or go
with a modern solution, the orange long life coolant Havoline Dexcool,
about $9.00/gal.  A lot has changed since our cars were last made in
1990. Perfect for waterboxers, and has a five year life.  See
http://www.theherd.com/articles/dex_cool.html for a technical discussion
from the Impala enthusiast list.  Just remember that you MUST remove ALL
of the old stuff to get this longevity (as little at 10% left will still
break down into enough acid to cause corrosion), and that will require
removing the hoses from the radiator after flushing to completely drain
the system.

I use it in all my cars, it is about time somebody invented a coolant
that doesn't break down and form acids that corrode our engines.  This
is one way we old car owners can benefit from the current drive by the
manufacturers to reduce the required maintenance on new cars.  All of
them are striving for 100,000 miles with only oil changes, and you can
bet they are working on systems that will eliminate them too!
--
Stuart MacMillan
Seattle

'84 Vanagon Westfalia
'65 MGB (Driven since 1969)
'74 MGB GT (Restoring)

Assisting on Restoration:
'72 MGB GT (Daughter's)
'64 MGB (Son's)

Parts cars:
'68 & '73 MGB, '67 MGB GT