Anti freeze should be a 50/50 mix water/a-freeze and my manual says quantity is approx' 10.6L or 18.7 pints.
I would make up a ready mixed 20 pints and keep whatever is left over for topping up.
Pilote, July 2006
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I can answer this question...
How much antifreeze ia required for a talbot express 1300d motorhome?