Reading my specs right our old subes do a 5.5 litre cooling system capacity

 

1.2 litres of that is included but is the reservoir bottle!

 

Think 81 rad is 1.2 litres and 82 rad capacity not listed ( due to shame its less than ea81?)

 

Not an awful lot of coolant actually in the engine

It takes about a gallon of coolant to refill the engine.  Coolant can be reused from a previously clean catch pan, by pouring it through paper towels that are folded inside of a funnel, sitting on a clean milk jug.  You just want to make sure all of the coolant gets filtered by the paper towels.