" TR8's are know to
eventually clog the radiator. Something to do with the aluminum block and
maybe a more
knowledgeable lister who knows metallurgy can tell us why."
It has only a bit to do with metallurgy, and more to do with coolant
chemistry. I had a new '76 TR7 when I lived in Houston and had the same
problem. The coolant that BL usd in these cars was not properly formulated
for aluminum engine components. Basically, it dissolved the aluminum out of
the head and deposited it on the cool surface inside the radiator. This
unintended cladding degraded the heat transfer coefficient of the radiator.
A lot of American cars had the same problem until GM and Union Carbide
developed what is now the silicone/silicate coolant inhibitor package that
we know as Prestone. The silicate coats [actually impregnates] the aluminum
and prevents the acid in the degrading coolant [glycol oxidizes to organic
acid] from attacking it.
These coolants are not that great in all cat iron, steel and brass engine &
cooling systems like the TR2-6. Their drawback is that the silicate can
polymerize and clog the radiator tubes with gel.
Glenn C
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